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org.scalatest.flatspec.AnyFlatSpec.scala Maven / Gradle / Ivy

/*
 * Copyright 2001-2013 Artima, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.scalatest.flatspec

import org.scalatest.{Finders, Suite}

/**
 * Facilitates a “behavior-driven” style of development (BDD), in which tests
 * are combined with text that specifies the behavior the tests verify.
 * 

 *
 * 

 * Recommended Usage:
 * Class AnyFlatSpec is a good first step for teams wishing to move from xUnit to BDD, because its structure is flat like xUnit, so simple and familiar, 
 * but the test names must be written in a specification style: “X should Y,” “A must B,” etc.  
 * 
 * 
 * 

 * Trait AnyFlatSpec is so named because
 * your specification text and tests line up flat against the left-side indentation level, with no nesting needed.
 * Here's an example AnyFlatSpec:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * 
 * class SetSpec extends AnyFlatSpec {
 * 
 *   behavior of "An empty Set"
 *   
 *   it should "have size 0" in {
 *     assert(Set.empty.size === 0)
 *   }
 *     
 *   it should "produce NoSuchElementException when head is invoked" in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * Note: you can use must or can as well as should in a AnyFlatSpec. For example, instead of
 * it should "have..., you could write it must "have... or it can "have....
 * 
 *
 * 

 * Instead of using a behavior of clause, you can alternatively use a shorthand syntax in which you replace
 * the first it with the subject string, like this:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * 
 * class SetSpec extends AnyFlatSpec {
 *   
 *   "An empty Set" should "have size 0" in {
 *     assert(Set.empty.size === 0)
 *   }
 *     
 *   it should "produce NoSuchElementException when head is invoked" in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * Running either of the two previous versions of SetSpec in the Scala interpreter would yield:
 * 
 * 
 * 
 * An empty Set
 * - should have size 0
 * - should produce NoSuchElementException when head is invoked
 * 
 *
 * 

 * In a AnyFlatSpec you write a one (or more) sentence specification for each bit of behavior you wish to
 * specify and test. Each specification sentence has a
 * "subject," which is sometimes called the system under test (or SUT). The 
 * subject is the entity being specified and tested and also serves as the subject of the sentences you write for each test.
 * Often you will want to write multiple tests for the same subject. In a AnyFlatSpec, you name the subject once,
 * with a behavior of clause or its shorthand, then write tests for that subject with it should/must/can "do something" phrases.
 * Each it refers to the most recently declared subject. For example, the four tests shown in this snippet are all testing
 * a stack that contains one item:
 * 
 * 
 * 
 * behavior of "A Stack (with one item)"
 *
 * it should "be non-empty" in {}
 *
 * it should "return the top item on peek" in {}
 *
 * it should "not remove the top item on peek" in {}
 *
 * it should "remove the top item on pop" in {}
 * 
 * 
 * 

 * The same is true if the tests are written using the shorthand notation:
 * 
 *
 * 
 * "A Stack (with one item)" should "be non-empty" in {}
 *
 * it should "return the top item on peek" in {}
 *
 * it should "not remove the top item on peek" in {}
 *
 * it should "remove the top item on pop" in {}
 * 
 * 
 * 

 * In a AnyFlatSpec, therefore, to figure out what "it" means, you just scan vertically until you find the most
 * recent use of behavior of or the shorthand notation.
 * 
 *
 * 

 * Because sometimes the subject could be plural, you can alternatively use they instead of it:
 * 
 *
 * 
 * "The combinators" should "be easy to learn" in {}
 *
 * they should "be efficient" in {}
 *
 * they should "do something cool" in {}
 * 
 * 
 * 

 * A AnyFlatSpec's lifecycle has two phases: the registration phase and the
 * ready phase. It starts in registration phase and enters ready phase the first time
 * run is called on it. It then remains in ready phase for the remainder of its lifetime.
 * 
 *
 * 

 * Tests can only be registered while the AnyFlatSpec is
 * in its registration phase. Any attempt to register a test after the AnyFlatSpec has
 * entered its ready phase, i.e., after run has been invoked on the AnyFlatSpec,
 * will be met with a thrown TestRegistrationClosedException. The recommended style
 * of using AnyFlatSpec is to register tests during object construction as is done in all
 * the examples shown here. If you keep to the recommended style, you should never see a
 * TestRegistrationClosedException.
 * 
 *
 * 
Ignored tests
 *
 * To support the common use case of temporarily disabling a test, with the
 * good intention of resurrecting the test at a later time, AnyFlatSpec provides a method
 * ignore that can be used instead of it or they to register a test. For example, to temporarily
 * disable the test with the name "An empty Set should produce NoSuchElementException when head is invoked", just
 * change “it” into “ignore,” like this:
 * 

 *
 * 
 * package org.scalatest.examples.flatspec.ignore
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * 
 * class SetSpec extends AnyFlatSpec {
 *   
 *   "An empty Set" should "have size 0" in {
 *     assert(Set.empty.size === 0)
 *   }
 *     
 *   ignore should "produce NoSuchElementException when head is invoked" in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * If you run this version of SetSpec with:
 * 
 *
 * 
 * scala> org.scalatest.run(new SetSpec)
 * 
 *
 * 

 * It will run only the first test and report that the second test was ignored:
 * 
 *
 * 
 * An empty Set
 * - should have size 0
 * - should produce NoSuchElementException when head is invoked !!! IGNORED !!!
 * 
 *
 * 

 * When using shorthand notation, you won't have an it to change into ignore for
 * the first test of each new subject. To ignore such tests, you must instead change in to ignore.
 * For example, to temporarily disable the test with the name "An empty Set should have size 0",
 * change “in” into “ignore” like this:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.ignoreafter
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * 
 * class SetSpec extends AnyFlatSpec {
 *   
 *   "An empty Set" should "have size 0" ignore {
 *     assert(Set.empty.size === 0)
 *   }
 *     
 *   it should "produce NoSuchElementException when head is invoked" in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * If you run this version of StackSpec with:
 * 
 *
 * 
 * scala> org.scalatest.run(new SetSpec)
 * 
 *
 * 

 * It will run only the second test and report that the first test was ignored:
 * 
 *
 * 
 * An empty Set
 * - should have size 0 !!! IGNORED !!!
 * - should produce NoSuchElementException when head is invoked
 * 
 *
 * 

 * If you wish to temporarily ignore an entire suite of tests, you can (on the JVM, not Scala.js) annotate the test class with @Ignore, like this:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.ignoreall
 * 
 * import org.scalatest._
 * 
 * @Ignore
 * class SetSpec extends flatspec.AnyFlatSpec {
 * 
 *   "An empty Set" should "have size 0" in {
 *     assert(Set.empty.size === 0)
 *   }
 * 
 *   it should "produce NoSuchElementException when head is invoked" in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * When you mark a test class with a tag annotation, ScalaTest will mark each test defined in that class with that tag.
 * Thus, marking the SetSpec in the above example with the @Ignore tag annotation means that both tests
 * in the class will be ignored. If you run the above SetSpec in the Scala interpreter, you'll see:
 * 
 *
 * 
 * scala> org.scalatest.run(new SetSpec)
 * SetSpec:
 * An empty Set
 * - should have size 0 !!! IGNORED !!!
 * - should produce NoSuchElementException when head is invoked !!! IGNORED !!!
 * 
 *
 * 

 * Note that marking a test class as ignored won't prevent it from being discovered by ScalaTest. Ignored classes
 * will be discovered and run, and all their tests will be reported as ignored. This is intended to keep the ignored
 * class visible, to encourage the developers to eventually fix and “un-ignore” it. If you want to
 * prevent a class from being discovered at all (on the JVM, not Scala.js), use the DoNotDiscover annotation instead.
 * 
 *
 * 
Informers
 *
 * 

 * One of the parameters to AnyFlatSpec's run method is a Reporter, which
 * will collect and report information about the running suite of tests.
 * Information about suites and tests that were run, whether tests succeeded or failed, 
 * and tests that were ignored will be passed to the Reporter as the suite runs.
 * Most often the reporting done by default by AnyFlatSpec's methods will be sufficient, but
 * occasionally you may wish to provide custom information to the Reporter from a test.
 * For this purpose, an Informer that will forward information to the current Reporter
 * is provided via the info parameterless method.
 * You can pass the extra information to the Informer via its apply method.
 * The Informer will then pass the information to the Reporter via an InfoProvided event.
 * 
 * 
 * 

 * One use case for the Informer is to pass more information about a specification to the reporter. For example,
 * the GivenWhenThen trait provides methods that use the implicit info provided by FlatSpec
 * to pass such information to the reporter.  Here's an example:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.info
 * 
 * import collection.mutable
 * import org.scalatest._
 * 
 * class SetSpec extends flatspec.AnyFlatSpec with GivenWhenThen {
 *   
 *   "A mutable Set" should "allow an element to be added" in {
 *     Given("an empty mutable Set")
 *     val set = mutable.Set.empty[String]
 * 
 *     When("an element is added")
 *     set += "clarity"
 * 
 *     Then("the Set should have size 1")
 *     assert(set.size === 1)
 * 
 *     And("the Set should contain the added element")
 *     assert(set.contains("clarity"))
 * 
 *     info("That's all folks!")
 *   }
 * }
 * 
 *
 * 

 * If you run this AnyFlatSpec from the interpreter, you will see the following output:
 * 
 *
 * 
 * scala> org.scalatest.run(new SetSpec)
 * SetSpec:
 * A mutable Set
 * - should allow an element to be added
 *   + Given an empty mutable Set 
 *   + When an element is added 
 *   + Then the Set should have size 1 
 *   + And the Set should contain the added element 
 *   + That's all folks! 
 * 
 *
 * 
Documenters
 *
 * 

 * AnyFlatSpec also provides a markup method that returns a Documenter, which allows you to send
 * to the Reporter text formatted in Markdown syntax.
 * You can pass the extra information to the Documenter via its apply method.
 * The Documenter will then pass the information to the Reporter via an MarkupProvided event.
 * 
 *
 * 

 * Here's an example AnyFlatSpec that uses markup:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.markup
 *
 * import collection.mutable
 * import org.scalatest._
 *
 * class SetSpec extends flatspec.AnyFlatSpec with GivenWhenThen {
 * 
 *   markup { """
 *
 * Mutable Set
 * -----------
 *
 * A set is a collection that contains no duplicate elements.
 *
 * To implement a concrete mutable set, you need to provide implementations
 * of the following methods:
 *
 *     def contains(elem: A): Boolean
 *     def iterator: Iterator[A]
 *     def += (elem: A): this.type
 *     def -= (elem: A): this.type
 *
 * If you wish that methods like `take`,
 * `drop`, `filter` return the same kind of set,
 * you should also override:
 *
 *     def empty: This
 *
 * It is also good idea to override methods `foreach` and
 * `size` for efficiency.
 *
 *   """ }
 *
 *   "A mutable Set" should "allow an element to be added" in {
 *     Given("an empty mutable Set")
 *     val set = mutable.Set.empty[String]
 *
 *     When("an element is added")
 *     set += "clarity"
 *
 *     Then("the Set should have size 1")
 *     assert(set.size === 1)
 *
 *     And("the Set should contain the added element")
 *     assert(set.contains("clarity"))
 *
 *     markup("This test finished with a **bold** statement!")
 *   }
 * }
 * 
 *
 * 

 * Although all of ScalaTest's built-in reporters will display the markup text in some form,
 * the HTML reporter will format the markup information into HTML. Thus, the main purpose of markup is to
 * add nicely formatted text to HTML reports. Here's what the above SetSpec would look like in the HTML reporter:
 * 
 *
 * 
 *
 * 
Notifiers and alerters
 *
 * 

 * ScalaTest records text passed to info and markup during tests, and sends the recorded text in the recordedEvents field of 
 * test completion events like TestSucceeded and TestFailed. This allows string reporters (like the standard out reporter) to show
 * info and markup text after the test name in a color determined by the outcome of the test. For example, if the test fails, string
 * reporters will show the info and markup text in red. If a test succeeds, string reporters will show the info
 * and markup text in green. While this approach helps the readability of reports, it means that you can't use info to get status
 * updates from long running tests.
 * 
 *
 * 

 * To get immediate (i.e., non-recorded) notifications from tests, you can use note (a Notifier) and alert
 * (an Alerter). Here's an example showing the differences:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.note
 *
 * import collection.mutable
 * import org.scalatest._
 *
 * class SetSpec extends flatspec.AnyFlatSpec {
 *
 *   "A mutable Set" should "allow an element to be added" in {
 *
 *     info("info is recorded")
 *     markup("markup is *also* recorded")
 *     note("notes are sent immediately")
 *     alert("alerts are also sent immediately")
 *
 *     val set = mutable.Set.empty[String]
 *     set += "clarity"
 *     assert(set.size === 1)
 *     assert(set.contains("clarity"))
 *   }
 * }
 * 
 *
 * 

 * Because note and alert information is sent immediately, it will appear before the test name in string reporters, and its color will
 * be unrelated to the ultimate outcome of the test: note text will always appear in green, alert text will always appear in yellow.
 * Here's an example:
 * 
 *
 * 
 * scala> org.scalatest.run(new SetSpec)
 * SetSpec:
 * A mutable Set
 *   + notes are sent immediately
 *   + alerts are also sent immediately
 * - should allow an element to be added
 *   + info is recorded 
 *   + markup is *also* recorded
 * 
 *
 * 

 * Another example is slowpoke notifications.
 * If you find a test is taking a long time to complete, but you're not sure which test, you can enable 
 * slowpoke notifications. ScalaTest will use an Alerter to fire an event whenever a test has been running
 * longer than a specified amount of time.
 * 
 *
 * 

 * In summary, use info and markup for text that should form part of the specification output. Use
 * note and alert to send status notifications. (Because the HTML reporter is intended to produce a
 * readable, printable specification, info and markup text will appear in the HTML report, but
 * note and alert text will not.)
 * 
 *
 * 
Pending tests
 *
 * 

 * A pending test is one that has been given a name but is not yet implemented. The purpose of
 * pending tests is to facilitate a style of testing in which documentation of behavior is sketched
 * out before tests are written to verify that behavior (and often, before the behavior of
 * the system being tested is itself implemented). Such sketches form a kind of specification of
 * what tests and functionality to implement later.
 * 
 *
 * 

 * To support this style of testing, a test can be given a name that specifies one
 * bit of behavior required by the system being tested. The test can also include some code that
 * sends more information about the behavior to the reporter when the tests run. At the end of the test,
 * it can call method pending, which will cause it to complete abruptly with TestPendingException.
 * 
 *
 * 

 * Because tests in ScalaTest can be designated as pending with TestPendingException, both the test name and any information
 * sent to the reporter when running the test can appear in the report of a test run. (In other words,
 * the code of a pending test is executed just like any other test.) However, because the test completes abruptly
 * with TestPendingException, the test will be reported as pending, to indicate
 * the actual test, and possibly the functionality it is intended to test, has not yet been implemented.
 * You can mark tests as pending in FlatSpec like this:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.pending
 * 
 * import org.scalatest._
 * 
 * class SetSpec extends flatspec.AnyFlatSpec {
 * 
 *   "An empty Set" should "have size 0" in (pending)
 *     
 *   it should "produce NoSuchElementException when head is invoked" in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * If you run this version of AnyFlatSpec with:
 * 
 *
 * 
 * scala> org.scalatest.run(new SetSpec)
 * 
 *
 * 

 * It will run both tests but report that An empty Set should have size 0 is pending. You'll see:
 * 
 *
 * 
 * An empty Set
 * - should have size 0 (pending)
 * - should produce NoSuchElementException when head is invoked
 * 
 * 
 * 

 * One difference between an ignored test and a pending one is that an ignored test is intended to be used during a
 * significant refactorings of the code under test, when tests break and you don't want to spend the time to fix
 * all of them immediately. You can mark some of those broken tests as ignored temporarily, so that you can focus the red
 * bar on just failing tests you actually want to fix immediately. Later you can go back and fix the ignored tests.
 * In other words, by ignoring some failing tests temporarily, you can more easily notice failed tests that you actually
 * want to fix. By contrast, a pending test is intended to be used before a test and/or the code under test is written.
 * Pending indicates you've decided to write a test for a bit of behavior, but either you haven't written the test yet, or
 * have only written part of it, or perhaps you've written the test but don't want to implement the behavior it tests
 * until after you've implemented a different bit of behavior you realized you need first. Thus ignored tests are designed
 * to facilitate refactoring of existing code whereas pending tests are designed to facilitate the creation of new code.
 * 
 *
 * 

 * One other difference between ignored and pending tests is that ignored tests are implemented as a test tag that is
 * excluded by default. Thus an ignored test is never executed. By contrast, a pending test is implemented as a
 * test that throws TestPendingException (which is what calling the pending method does). Thus
 * the body of pending tests are executed up until they throw TestPendingException. The reason for this difference
 * is that it enables your unfinished test to send InfoProvided messages to the reporter before it completes
 * abruptly with TestPendingException, as shown in the previous example on Informers
 * that used the GivenWhenThen trait. For example, the following snippet in a AnyFlatSpec:
 * 
 *
 * 
 *  "The Scala language" must "add correctly" in { 
 *     Given("two integers")
 *     When("they are added")
 *     Then("the result is the sum of the two numbers")
 *     pending
 *   }
 *   // ...
 * 
 *
 * 

 * Would yield the following output when run in the interpreter:
 * 
 *
 * 
 * The Scala language
 * - must add correctly (pending)
 *   + Given two integers 
 *   + When they are added 
 *   + Then the result is the sum of the two numbers 
 * 
 *
 * 
Tagging tests
 *
 * A AnyFlatSpec's tests may be classified into groups by tagging them with string names.
 * As with any suite, when executing a AnyFlatSpec, groups of tests can
 * optionally be included and/or excluded. To tag a AnyFlatSpec's tests,
 * you pass objects that extend class org.scalatest.Tag to methods
 * that register tests. Class Tag takes one parameter, a string name.  If you have
 * created tag annotation interfaces as described in the Tag documentation, then you
 * will probably want to use tag names on your test functions that match. To do so, simply 
 * pass the fully qualified names of the tag interfaces to the Tag constructor. For example, if you've
 * defined a tag annotation interface with fully qualified name, 
 * com.mycompany.tags.DbTest, then you could
 * create a matching tag for AnyFlatSpecs like this:
 * 

 *
 * 
 * package org.scalatest.examples.flatspec.tagging
 * 
 * import org.scalatest.Tag
 * 
 * object DbTest extends Tag("com.mycompany.tags.DbTest")
 * 
 *
 * 

 * Given these definitions, you could place AnyFlatSpec tests into groups with tags like this:
 * 
 *
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * import org.scalatest.tagobjects.Slow
 * 
 * class SetSpec extends AnyFlatSpec {
 * 
 *   behavior of "An empty Set"
 *   
 *   it should "have size 0" taggedAs(Slow) in {
 *     assert(Set.empty.size === 0)
 *   }
 *     
 *   it should "produce NoSuchElementException when head is invoked" taggedAs(Slow, DbTest) in {
 *     assertThrows[NoSuchElementException] {
 *       Set.empty.head
 *     }
 *   }
 * }
 * 
 *
 * 

 * This code marks both tests with the org.scalatest.tags.Slow tag, 
 * and the second test with the com.mycompany.tags.DbTest tag.
 * 
 *
 * 

 * The run method takes a Filter, whose constructor takes an optional
 * Set[String] called tagsToInclude and a Set[String] called
 * tagsToExclude. If tagsToInclude is None, all tests will be run
 * except those those belonging to tags listed in the
 * tagsToExclude Set. If tagsToInclude is defined, only tests
 * belonging to tags mentioned in the tagsToInclude set, and not mentioned in tagsToExclude,
 * will be run.
 * 
 *
 * 

 * It is recommended, though not required, that you create a corresponding tag annotation when you
 * create a Tag object. A tag annotation (on the JVM, not Scala.js) allows you to tag all the tests of a AnyFlatSpec in
 * one stroke by annotating the class. For more information and examples, see the
 * documentation for class Tag. On Scala.js, to tag all tests of a suite, you'll need to
 * tag each test individually at the test site.
 * 
 *
 * 
 * 
Shared fixtures
 *
 * 

 * A test fixture is composed of the objects and other artifacts (files, sockets, database
 * connections, etc.) tests use to do their work.
 * When multiple tests need to work with the same fixtures, it is important to try and avoid
 * duplicating the fixture code across those tests. The more code duplication you have in your
 * tests, the greater drag the tests will have on refactoring the actual production code.
 * 
 *
 * 

 * ScalaTest recommends three techniques to eliminate such code duplication:
 * 
 *
 * 

 * 
Refactor using Scala
 * 
Override withFixture
 * 
Mix in a before-and-after trait
 * 
 *
 * 
Each technique is geared towards helping you reduce code duplication without introducing
 * instance vars, shared mutable objects, or other dependencies between tests. Eliminating shared
 * mutable state across tests will make your test code easier to reason about and more amenable for parallel
 * test execution.
The following sections
 * describe these techniques, including explaining the recommended usage
 * for each. But first, here's a table summarizing the options:
 *
 * 
 *
 * 
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 
 *   
 *   
 * 
 *
 * 

 *     Refactor using Scala when different tests need different fixtures.
 *   

 *     get-fixture methods
 *   

 *     The extract method refactor helps you create a fresh instances of mutable fixture objects in each test
 *     that needs them, but doesn't help you clean them up when you're done.
 *   

 *     fixture-context objects
 *   

 *     By placing fixture methods and fields into traits, you can easily give each test just the newly created
 *     fixtures it needs by mixing together traits.  Use this technique when you need different combinations
 *     of mutable fixture objects in different tests, and don't need to clean up after.
 *   

 *     loan-fixture methods
 *   

 *     Factor out dupicate code with the loan pattern when different tests need different fixtures that must be cleaned up afterwards.
 *   

 *     Override withFixture when most or all tests need the same fixture.
 *   

 *     
 *       withFixture(NoArgTest)
 *     

 *     

 *     The recommended default approach when most or all tests need the same fixture treatment. This general technique
 *     allows you, for example, to perform side effects at the beginning and end of all or most tests, 
 *     transform the outcome of tests, retry tests, make decisions based on test names, tags, or other test data.
 *     Use this technique unless:
 *     
 *  

 *  
Different tests need different fixtures (refactor using Scala instead)
 *  
An exception in fixture code should abort the suite, not fail the test (use a before-and-after trait instead)
 *  
You have objects to pass into tests (override withFixture(OneArgTest) instead)
 *  
 *  

 *     
 *       withFixture(OneArgTest)
 *     
 *   

 *     Use when you want to pass the same fixture object or objects as a parameter into all or most tests.
 *   

 *     Mix in a before-and-after trait when you want an aborted suite, not a failed test, if the fixture code fails.
 *   

 *     BeforeAndAfter
 *   

 *     Use this boilerplate-buster when you need to perform the same side-effects before and/or after tests, rather than at the beginning or end of tests.
 *   

 *     BeforeAndAfterEach
 *   

 *     Use when you want to stack traits that perform the same side-effects before and/or after tests, rather than at the beginning or end of tests.
 *   
 *
 * 
 * 
Calling get-fixture methods
 *
 * 

 * If you need to create the same mutable fixture objects in multiple tests, and don't need to clean them up after using them, the simplest approach is to write one or
 * more get-fixture methods. A get-fixture method returns a new instance of a needed fixture object (or a holder object containing
 * multiple fixture objects) each time it is called. You can call a get-fixture method at the beginning of each
 * test that needs the fixture, storing the returned object or objects in local variables. Here's an example:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.getfixture
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * import collection.mutable.ListBuffer
 * 
 * class ExampleSpec extends AnyFlatSpec {
 * 
 *   class Fixture {
 *     val builder = new StringBuilder("ScalaTest is ")
 *     val buffer = new ListBuffer[String]
 *   }
 *
 *   def fixture = new Fixture
 *   
 *   "Testing" should "be easy" in {
 *     val f = fixture
 *     f.builder.append("easy!")
 *     assert(f.builder.toString === "ScalaTest is easy!")
 *     assert(f.buffer.isEmpty)
 *     f.buffer += "sweet"
 *   }
 *   
 *   it should "be fun" in {
 *     val f = fixture
 *     f.builder.append("fun!")
 *     assert(f.builder.toString === "ScalaTest is fun!")
 *     assert(f.buffer.isEmpty)
 *   }
 * }
 * 
 *
 * 

 * The “f.” in front of each use of a fixture object provides a visual indication of which objects 
 * are part of the fixture, but if you prefer, you can import the the members with “import f._” and use the names directly.
 * 
 *
 * 

 * If you need to configure fixture objects differently in different tests, you can pass configuration into the get-fixture method. For example, if you could pass
 * in an initial value for a mutable fixture object as a parameter to the get-fixture method.
 * 
 *
 * 
 * 
Instantiating fixture-context objects 
 *
 * 

 * An alternate technique that is especially useful when different tests need different combinations of fixture objects is to define the fixture objects as instance variables
 * of fixture-context objects whose instantiation forms the body of tests. Like get-fixture methods, fixture-context objects are only
 * appropriate if you don't need to clean up the fixtures after using them.
 * 
 *
 * 

 * To use this technique, you define instance variables intialized with fixture objects in traits and/or classes, then in each test instantiate an object that
 * contains just the fixture objects needed by the test. Traits allow you to mix together just the fixture objects needed by each test, whereas classes
 * allow you to pass data in via a constructor to configure the fixture objects. Here's an example in which fixture objects are partitioned into two traits
 * and each test just mixes together the traits it needs:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.fixturecontext
 * 
 * import collection.mutable.ListBuffer
 * import org.scalatest.flatspec.AnyFlatSpec
 * 
 * class ExampleSpec extends AnyFlatSpec {
 * 
 *   trait Builder {
 *     val builder = new StringBuilder("ScalaTest is ")
 *   }
 * 
 *   trait Buffer {
 *     val buffer = ListBuffer("ScalaTest", "is")
 *   }
 * 
 *   // This test needs the StringBuilder fixture
 *   "Testing" should "be productive" in new Builder {
 *     builder.append("productive!")
 *     assert(builder.toString === "ScalaTest is productive!")
 *   }
 * 
 *   // This test needs the ListBuffer[String] fixture
 *   "Test code" should "be readable" in new Buffer {
 *     buffer += ("readable!")
 *     assert(buffer === List("ScalaTest", "is", "readable!"))
 *   }
 * 
 *   // This test needs both the StringBuilder and ListBuffer
 *   it should "be clear and concise" in new Builder with Buffer {
 *     builder.append("clear!")
 *     buffer += ("concise!")
 *     assert(builder.toString === "ScalaTest is clear!")
 *     assert(buffer === List("ScalaTest", "is", "concise!"))
 *   }
 * }
 * 
 *
 * 
 * 
Overriding withFixture(NoArgTest)
 *
 * 

 * Although the get-fixture method and fixture-context object approaches take care of setting up a fixture at the beginning of each
 * test, they don't address the problem of cleaning up a fixture at the end of the test. If you just need to perform a side-effect at the beginning or end of
 * a test, and don't need to actually pass any fixture objects into the test, you can override withFixture(NoArgTest), one of ScalaTest's
 * lifecycle methods defined in trait Suite.
 * 
 *
 * 

 * Trait Suite's implementation of runTest passes a no-arg test function to withFixture(NoArgTest). It is withFixture's
 * responsibility to invoke that test function. Suite's implementation of withFixture simply
 * invokes the function, like this:
 * 
 *
 * 
 * // Default implementation in trait Suite
 * protected def withFixture(test: NoArgTest) = {
 *   test()
 * }
 * 
 *
 * 

 * You can, therefore, override withFixture to perform setup before and/or cleanup after invoking the test function. If
 * you have cleanup to perform, you should invoke the test function inside a try block and perform the cleanup in
 * a finally clause, in case an exception propagates back through withFixture. (If a test fails because of an exception,
 * the test function invoked by withFixture will result in a [[org.scalatest.Failed Failed]] wrapping the exception. Nevertheless,
 * best practice is to perform cleanup in a finally clause just in case an exception occurs.)
 * 
 *
 * 

 * The withFixture method is designed to be stacked, and to enable this, you should always call the super implementation
 * of withFixture, and let it invoke the test function rather than invoking the test function directly. That is to say, instead of writing
 * “test()”, you should write “super.withFixture(test)”, like this:
 * 
 *
 * 
 * // Your implementation
 * override def withFixture(test: NoArgTest) = {
 *   // Perform setup
 *   try super.withFixture(test) // Invoke the test function
 *   finally {
 *     // Perform cleanup
 *   }
 * }
 * 
 *
 * 

 * Here's an example in which withFixture(NoArgTest) is used to take a snapshot of the working directory if a test fails, and 
 * send that information to the reporter:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.noargtest
 * 
 * import java.io.File
 * import org.scalatest._
 * 
 * class ExampleSpec extends flatspec.AnyFlatSpec {
 * 
 *   override def withFixture(test: NoArgTest) = {
 * 
 *     super.withFixture(test) match {
 *       case failed: Failed =>
 *         val currDir = new File(".")
 *         val fileNames = currDir.list()
 *         info("Dir snapshot: " + fileNames.mkString(", "))
 *         failed
 *       case other => other
 *     }
 *   }
 * 
 *   "This test" should "succeed" in {
 *     assert(1 + 1 === 2)
 *   }
 * 
 *   it should "fail" in {
 *     assert(1 + 1 === 3)
 *   }
 * }
 * 
 *
 * 

 * Running this version of ExampleSuite in the interpreter in a directory with two files, hello.txt and world.txt
 * would give the following output:
 * 
 *
 * 
 * scala> org.scalatest.run(new ExampleSuite)
 * ExampleSuite:
 * This test
 * - should succeed
 * - should fail *** FAILED ***
 *   2 did not equal 3 (:33)
 *   + Dir snapshot: hello.txt, world.txt 
 * 
 *
 * 

 * Note that the NoArgTest passed to withFixture, in addition to
 * an apply method that executes the test, also includes [[org.scalatest.TestData TestData]] such as the test name and the config
 * map passed to runTest. Thus you can also use the test name and configuration objects in your withFixture
 * implementation.
 * 
 *
 * 
 * 
Calling loan-fixture methods
 *
 * 

 * If you need to both pass a fixture object into a test and perform cleanup at the end of the test, you'll need to use the loan pattern.
 * If different tests need different fixtures that require cleanup, you can implement the loan pattern directly by writing loan-fixture methods.
 * A loan-fixture method takes a function whose body forms part or all of a test's code. It creates a fixture, passes it to the test code by invoking the
 * function, then cleans up the fixture after the function returns.
 * 
 *
 * 

 * The following example shows three tests that use two fixtures, a database and a file. Both require cleanup after, so each is provided via a
 * loan-fixture method. (In this example, the database is simulated with a StringBuffer.)
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.loanfixture
 * 
 * import java.util.concurrent.ConcurrentHashMap
 * 
 * object DbServer { // Simulating a database server
 *   type Db = StringBuffer
 *   private val databases = new ConcurrentHashMap[String, Db]
 *   def createDb(name: String): Db = {
 *     val db = new StringBuffer
 *     databases.put(name, db)
 *     db
 *   }
 *   def removeDb(name: String) {
 *     databases.remove(name)
 *   }
 * }
 * 
 * import org.scalatest.flatspec.AnyFlatSpec
 * import DbServer._
 * import java.util.UUID.randomUUID
 * import java.io._
 * 
 * class ExampleSpec extends flatspec.AnyFlatSpec {
 * 
 *   def withDatabase(testCode: Db => Any) {
 *     val dbName = randomUUID.toString
 *     val db = createDb(dbName) // create the fixture
 *     try {
 *       db.append("ScalaTest is ") // perform setup
 *       testCode(db) // "loan" the fixture to the test
 *     }
 *     finally removeDb(dbName) // clean up the fixture
 *   }
 * 
 *   def withFile(testCode: (File, FileWriter) => Any) {
 *     val file = File.createTempFile("hello", "world") // create the fixture
 *     val writer = new FileWriter(file)
 *     try {
 *       writer.write("ScalaTest is ") // set up the fixture
 *       testCode(file, writer) // "loan" the fixture to the test
 *     }
 *     finally writer.close() // clean up the fixture
 *   }
 * 
 *   // This test needs the file fixture
 *   "Testing" should "be productive" in withFile { (file, writer) =>
 *     writer.write("productive!")
 *     writer.flush()
 *     assert(file.length === 24)
 *   }
 *   
 *   // This test needs the database fixture
 *   "Test code" should "be readable" in withDatabase { db =>
 *     db.append("readable!")
 *     assert(db.toString === "ScalaTest is readable!")
 *   }
 * 
 *   // This test needs both the file and the database
 *   it should "be clear and concise" in withDatabase { db =>
 *     withFile { (file, writer) => // loan-fixture methods compose
 *       db.append("clear!")
 *       writer.write("concise!")
 *       writer.flush()
 *       assert(db.toString === "ScalaTest is clear!")
 *       assert(file.length === 21)
 *     }
 *   }
 * }
 * 
 *
 * 

 * As demonstrated by the last test, loan-fixture methods compose. Not only do loan-fixture methods allow you to
 * give each test the fixture it needs, they allow you to give a test multiple fixtures and clean everything up afterwards.
 * 
 *
 * 

 * Also demonstrated in this example is the technique of giving each test its own "fixture sandbox" to play in. When your fixtures
 * involve external side-effects, like creating files or databases, it is a good idea to give each file or database a unique name as is
 * done in this example. This keeps tests completely isolated, allowing you to run them in parallel if desired.
 * 
 *
 * 
 * 
Overriding withFixture(OneArgTest)
 *
 * 

 * If all or most tests need the same fixture, you can avoid some of the boilerplate of the loan-fixture method approach by using a FixtureAnyFlatSpec
 * and overriding withFixture(OneArgTest).
 * Each test in a FixtureAnyFlatSpec takes a fixture as a parameter, allowing you to pass the fixture into
 * the test. You must indicate the type of the fixture parameter by specifying FixtureParam, and implement a
 * withFixture method that takes a OneArgTest. This withFixture method is responsible for
 * invoking the one-arg test function, so you can perform fixture set up before, and clean up after, invoking and passing
 * the fixture into the test function.
 * 
 *
 * 

 * To enable the stacking of traits that define withFixture(NoArgTest), it is a good idea to let
 * withFixture(NoArgTest) invoke the test function instead of invoking the test
 * function directly. To do so, you'll need to convert the OneArgTest to a NoArgTest. You can do that by passing
 * the fixture object to the toNoArgTest method of OneArgTest. In other words, instead of
 * writing “test(theFixture)”, you'd delegate responsibility for
 * invoking the test function to the withFixture(NoArgTest) method of the same instance by writing:
 * 
 *
 * 
 * withFixture(test.toNoArgTest(theFixture))
 * 
 *
 * 

 * Here's a complete example:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.oneargtest
 * 
 * import org.scalatest.flatspec
 * import java.io._
 * 
 * class ExampleSpec extends flatspec.AnyFlatSpec {
 * 
 *   case class FixtureParam(file: File, writer: FileWriter)
 * 
 *   def withFixture(test: OneArgTest) = {
 *     val file = File.createTempFile("hello", "world") // create the fixture
 *     val writer = new FileWriter(file)
 *     val theFixture = FixtureParam(file, writer)
 * 
 *     try {
 *       writer.write("ScalaTest is ") // set up the fixture
 *       withFixture(test.toNoArgTest(theFixture)) // "loan" the fixture to the test
 *     }
 *     finally writer.close() // clean up the fixture
 *   }
 * 
 *   "Testing" should "be easy" in { f =>
 *     f.writer.write("easy!")
 *     f.writer.flush()
 *     assert(f.file.length === 18)
 *   }
 * 
 *   it should "be fun" in { f =>
 *     f.writer.write("fun!")
 *     f.writer.flush()
 *     assert(f.file.length === 17)
 *   }
 * }
 * 
 *
 * 

 * In this example, the tests actually required two fixture objects, a File and a FileWriter. In such situations you can
 * simply define the FixtureParam type to be a tuple containing the objects, or as is done in this example, a case class containing
 * the objects.  For more information on the withFixture(OneArgTest) technique, see the documentation for FixtureAnyFlatSpec.
 * 
 *
 * 
 * 
Mixing in BeforeAndAfter
 *
 * 

 * In all the shared fixture examples shown so far, the activities of creating, setting up, and cleaning up the fixture objects have been
 * performed during the test.  This means that if an exception occurs during any of these activities, it will be reported as a test failure.
 * Sometimes, however, you may want setup to happen before the test starts, and cleanup after the test has completed, so that if an
 * exception occurs during setup or cleanup, the entire suite aborts and no more tests are attempted. The simplest way to accomplish this in ScalaTest is
 * to mix in trait BeforeAndAfter.  With this trait you can denote a bit of code to run before each test
 * with before and/or after each test each test with after, like this:
 * 
 * 
 * 
 * package org.scalatest.examples.flatspec.beforeandafter
 * 
 * import org.scalatest._
 * import collection.mutable.ListBuffer
 * 
 * class ExampleSpec extends flatspec.AnyFlatSpec with BeforeAndAfter {
 * 
 *   val builder = new StringBuilder
 *   val buffer = new ListBuffer[String]
 * 
 *   before {
 *     builder.append("ScalaTest is ")
 *   }
 * 
 *   after {
 *     builder.clear()
 *     buffer.clear()
 *   }
 * 
 *   "Testing" should "be easy" in {
 *     builder.append("easy!")
 *     assert(builder.toString === "ScalaTest is easy!")
 *     assert(buffer.isEmpty)
 *     buffer += "sweet"
 *   }
 * 
 *   it should "be fun" in {
 *     builder.append("fun!")
 *     assert(builder.toString === "ScalaTest is fun!")
 *     assert(buffer.isEmpty)
 *   }
 * }
 * 
 *
 * 

 * Note that the only way before and after code can communicate with test code is via some side-effecting mechanism, commonly by
 * reassigning instance vars or by changing the state of mutable objects held from instance vals (as in this example). If using
 * instance vars or mutable objects held from instance vals you wouldn't be able to run tests in parallel in the same instance
 * of the test class (on the JVM, not Scala.js) unless you synchronized access to the shared, mutable state. This is why ScalaTest's ParallelTestExecution trait extends
 * OneInstancePerTest. By running each test in its own instance of the class, each test has its own copy of the instance variables, so you
 * don't need to synchronize. If you mixed ParallelTestExecution into the ExampleSuite above, the tests would run in parallel just fine
 * without any synchronization needed on the mutable StringBuilder and ListBuffer[String] objects.
 * 
 *
 * 

 * Although BeforeAndAfter provides a minimal-boilerplate way to execute code before and after tests, it isn't designed to enable stackable
 * traits, because the order of execution would be non-obvious.  If you want to factor out before and after code that is common to multiple test suites, you 
 * should use trait BeforeAndAfterEach instead, as shown later in the next section,
 * composing fixtures by stacking traits.
 * 
 *
 * 
Composing fixtures by stacking traits
 *
 * 

 * In larger projects, teams often end up with several different fixtures that test classes need in different combinations,
 * and possibly initialized (and cleaned up) in different orders. A good way to accomplish this in ScalaTest is to factor the individual
 * fixtures into traits that can be composed using the stackable trait pattern. This can be done, for example, by placing
 * withFixture methods in several traits, each of which call super.withFixture. Here's an example in
 * which the StringBuilder and ListBuffer[String] fixtures used in the previous examples have been
 * factored out into two stackable fixture traits named Builder and Buffer:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.composingwithfixture
 * 
 * import org.scalatest._
 * import collection.mutable.ListBuffer
 * 
 * trait Builder extends TestSuiteMixin { this: TestSuite =>
 * 
 *   val builder = new StringBuilder
 * 
 *   abstract override def withFixture(test: NoArgTest) = {
 *     builder.append("ScalaTest is ")
 *     try super.withFixture(test) // To be stackable, must call super.withFixture
 *     finally builder.clear()
 *   }
 * }
 * 
 * trait Buffer extends TestSuiteMixin { this: TestSuite =>
 * 
 *   val buffer = new ListBuffer[String]
 * 
 *   abstract override def withFixture(test: NoArgTest) = {
 *     try super.withFixture(test) // To be stackable, must call super.withFixture
 *     finally buffer.clear()
 *   }
 * }
 * 
 * class ExampleSpec extends flatspec.AnyFlatSpec with Builder with Buffer {
 * 
 *   "Testing" should "be easy" in {
 *     builder.append("easy!")
 *     assert(builder.toString === "ScalaTest is easy!")
 *     assert(buffer.isEmpty)
 *     buffer += "sweet"
 *   }
 * 
 *   it should "be fun" in {
 *     builder.append("fun!")
 *     assert(builder.toString === "ScalaTest is fun!")
 *     assert(buffer.isEmpty)
 *     buffer += "clear"
 *   }
 * }
 * 
 *
 * 

 * By mixing in both the Builder and Buffer traits, ExampleSuite gets both fixtures, which will be
 * initialized before each test and cleaned up after. The order the traits are mixed together determines the order of execution.
 * In this case, Builder is “super” to Buffer. If you wanted Buffer to be “super”
 * to Builder, you need only switch the order you mix them together, like this: 
 * 
 *
 * 
 * class Example2Spec extends flatspec.AnyFlatSpec with Buffer with Builder
 * 
 *
 * 

 * And if you only need one fixture you mix in only that trait:
 * 
 *
 * 
 * class Example3Spec extends flatspec.AnyFlatSpec with Builder
 * 
 *
 * 

 * Another way to create stackable fixture traits is by extending the BeforeAndAfterEach
 * and/or BeforeAndAfterAll traits.
 * BeforeAndAfterEach has a beforeEach method that will be run before each test (like JUnit's setUp),
 * and an afterEach method that will be run after (like JUnit's tearDown).
 * Similarly, BeforeAndAfterAll has a beforeAll method that will be run before all tests,
 * and an afterAll method that will be run after all tests. Here's what the previously shown example would look like if it
 * were rewritten to use the BeforeAndAfterEach methods instead of withFixture:
 * 
 *
 * 
 * package org.scalatest.examples.flatspec.composingbeforeandaftereach
 * 
 * import org.scalatest._
 * import collection.mutable.ListBuffer
 * 
 * trait Builder extends BeforeAndAfterEach { this: Suite =>
 * 
 *   val builder = new StringBuilder
 * 
 *   override def beforeEach() {
 *     builder.append("ScalaTest is ")
 *     super.beforeEach() // To be stackable, must call super.beforeEach
 *   }
 * 
 *   override def afterEach() {
 *     try super.afterEach() // To be stackable, must call super.afterEach
 *     finally builder.clear()
 *   }
 * }
 * 
 * trait Buffer extends BeforeAndAfterEach { this: Suite =>
 * 
 *   val buffer = new ListBuffer[String]
 * 
 *   override def afterEach() {
 *     try super.afterEach() // To be stackable, must call super.afterEach
 *     finally buffer.clear()
 *   }
 * }
 * 
 * class ExampleSpec extends flatspec.AnyFlatSpec with Builder with Buffer {
 * 
 *   "Testing" should "be easy" in {
 *     builder.append("easy!")
 *     assert(builder.toString === "ScalaTest is easy!")
 *     assert(buffer.isEmpty)
 *     buffer += "sweet"
 *   }
 * 
 *   it should "be fun" in {
 *     builder.append("fun!")
 *     assert(builder.toString === "ScalaTest is fun!")
 *     assert(buffer.isEmpty)
 *     buffer += "clear"
 *   }
 * }
 * 
 *
 * 

 * To get the same ordering as withFixture, place your super.beforeEach call at the end of each
 * beforeEach method, and the super.afterEach call at the beginning of each afterEach
 * method, as shown in the previous example. It is a good idea to invoke super.afterEach in a try
 * block and perform cleanup in a finally clause, as shown in the previous example, because this ensures the
 * cleanup code is performed even if super.afterEach throws an exception.
 * 
 *
 * 

 * The difference between stacking traits that extend BeforeAndAfterEach versus traits that implement withFixture is
 * that setup and cleanup code happens before and after the test in BeforeAndAfterEach, but at the beginning and
 * end of the test in withFixture. Thus if a withFixture method completes abruptly with an exception, it is
 * considered a failed test. By contrast, if any of the beforeEach or afterEach methods of BeforeAndAfterEach 
 * complete abruptly, it is considered an aborted suite, which will result in a SuiteAborted event.
 * 
 * 
 * 
Shared tests
 *
 * 

 * Sometimes you may want to run the same test code on different fixture objects. In other words, you may want to write tests that are "shared"
 * by different fixture objects.  To accomplish this in a AnyFlatSpec, you first place shared tests in behavior functions.
 * These behavior functions will be invoked during the construction phase of any AnyFlatSpec that uses them, so that the tests they
 * contain will be registered as tests in that AnyFlatSpec.  For example, given this stack class:
 * 
 *
 * 
 * import scala.collection.mutable.ListBuffer
 * 
 * class Stack[T] {
 *
 *   val MAX = 10
 *   private val buf = new ListBuffer[T]
 *
 *   def push(o: T) {
 *     if (!full)
 *       buf.prepend(o)
 *     else
 *       throw new IllegalStateException("can't push onto a full stack")
 *   }
 *
 *   def pop(): T = {
 *     if (!empty)
 *       buf.remove(0)
 *     else
 *       throw new IllegalStateException("can't pop an empty stack")
 *   }
 *
 *   def peek: T = {
 *     if (!empty)
 *       buf(0)
 *     else
 *       throw new IllegalStateException("can't pop an empty stack")
 *   }
 *
 *   def full: Boolean = buf.size == MAX
 *   def empty: Boolean = buf.size == 0
 *   def size = buf.size
 *
 *   override def toString = buf.mkString("Stack(", ", ", ")")
 * }
 * 
 *
 * 

 * You may want to test the Stack class in different states: empty, full, with one item, with one item less than capacity,
 * etc. You may find you have several tests that make sense any time the stack is non-empty. Thus you'd ideally want to run
 * those same tests for three stack fixture objects: a full stack, a stack with a one item, and a stack with one item less than
 * capacity. With shared tests, you can factor these tests out into a behavior function, into which you pass the
 * stack fixture to use when running the tests. So in your AnyFlatSpec for stack, you'd invoke the
 * behavior function three times, passing in each of the three stack fixtures so that the shared tests are run for all three fixtures. You
 * can define a behavior function that encapsulates these shared tests inside the AnyFlatSpec that uses them. If they are shared
 * between different AnyFlatSpecs, however, you could also define them in a separate trait that is mixed into each AnyFlatSpec
 * that uses them.
 * 
 *
 * 

 * For example, here the nonEmptyStack behavior function (in this case, a behavior method) is
 * defined in a trait along with another method containing shared tests for non-full stacks:
 * 
 * 
 * 
 * trait StackBehaviors { this: AnyFlatSpec =>
 * 
 *   def nonEmptyStack(newStack: => Stack[Int], lastItemAdded: Int) {
 *
 *     it should "be non-empty" in {
 *       assert(!newStack.empty)
 *     }
 *
 *     it should "return the top item on peek" in {
 *       assert(newStack.peek === lastItemAdded)
 *     }
 *
 *     it should "not remove the top item on peek" in {
 *       val stack = newStack
 *       val size = stack.size
 *       assert(stack.peek === lastItemAdded)
 *       assert(stack.size === size)
 *     }
 *
 *     it should "remove the top item on pop" in {
 *       val stack = newStack
 *       val size = stack.size
 *       assert(stack.pop === lastItemAdded)
 *       assert(stack.size === size - 1)
 *     }
 *   }
 *
 *   def nonFullStack(newStack: => Stack[Int]) {
 *
 *     it should "not be full" in {
 *       assert(!newStack.full)
 *     }
 *
 *     it should "add to the top on push" in {
 *       val stack = newStack
 *       val size = stack.size
 *       stack.push(7)
 *       assert(stack.size === size + 1)
 *       assert(stack.peek === 7)
 *     }
 *   }
 * }
 * 
 *
 *
 * 

 * Given these behavior functions, you could invoke them directly, but AnyFlatSpec offers a DSL for the purpose,
 * which looks like this:
 * 
 *
 * 
 * it should behave like nonEmptyStack(stackWithOneItem, lastValuePushed)
 * it should behave like nonFullStack(stackWithOneItem)
 * 
 *
 * 

 * If you prefer to use an imperative style to change fixtures, for example by mixing in BeforeAndAfterEach and
 * reassigning a stack var in beforeEach, you could write your behavior functions
 * in the context of that var, which means you wouldn't need to pass in the stack fixture because it would be
 * in scope already inside the behavior function. In that case, your code would look like this:
 * 
 *
 * 
 * it should behave like nonEmptyStack // assuming lastValuePushed is also in scope inside nonEmptyStack
 * it should behave like nonFullStack
 * 
 *
 * 

 * The recommended style, however, is the functional, pass-all-the-needed-values-in style. Here's an example:
 * 
 *
 * 
 * class SharedTestExampleSpec extends AnyFlatSpec with StackBehaviors {
 * 
 *   // Stack fixture creation methods
 *   def emptyStack = new Stack[Int]
 * 
 *   def fullStack = {
 *     val stack = new Stack[Int]
 *     for (i <- 0 until stack.MAX)
 *       stack.push(i)
 *     stack
 *   }
 * 
 *   def stackWithOneItem = {
 *     val stack = new Stack[Int]
 *     stack.push(9)
 *     stack
 *   }
 * 
 *   def stackWithOneItemLessThanCapacity = {
 *     val stack = new Stack[Int]
 *     for (i <- 1 to 9)
 *       stack.push(i)
 *     stack
 *   }
 * 
 *   val lastValuePushed = 9
 * 
 *   "A Stack (when empty)" should "be empty" in {
 *     assert(emptyStack.empty)
 *   }
 * 
 *   it should "complain on peek" in {
 *     assertThrows[IllegalStateException] {
 *       emptyStack.peek
 *     }
 *   }
 *
 *   it should "complain on pop" in {
 *     assertThrows[IllegalStateException] {
 *       emptyStack.pop
 *     }
 *   }
 * 
 *   "A Stack (with one item)" should behave like nonEmptyStack(stackWithOneItem, lastValuePushed)
 *
 *   it should behave like nonFullStack(stackWithOneItem)
 *     
 *   "A Stack (with one item less than capacity)" should behave like nonEmptyStack(stackWithOneItemLessThanCapacity, lastValuePushed)
 *
 *   it should behave like nonFullStack(stackWithOneItemLessThanCapacity)
 * 
 *   "A Stack (full)" should "be full" in {
 *     assert(fullStack.full)
 *   }
 * 
 *   it should behave like nonEmptyStack(fullStack, lastValuePushed)
 * 
 *   it should "complain on a push" in {
 *     assertThrows[IllegalStateException] {
 *       fullStack.push(10)
 *     }
 *   }
 * }
 * 
 *
 * 

 * If you load these classes into the Scala interpreter (with scalatest's JAR file on the class path), and execute it,
 * you'll see:
 * 
 *
 * 
 * scala> org.scalatest.run(new SharedTestExampleSpec)
 * A Stack (when empty)
 * - should be empty
 * - should complain on peek
 * - should complain on pop
 * A Stack (with one item) 
 * - should be non-empty
 * - should return the top item on peek
 * - should not remove the top item on peek
 * - should remove the top item on pop
 * - should not be full
 * - should add to the top on push
 * A Stack (with one item less than capacity) 
 * - should be non-empty
 * - should return the top item on peek
 * - should not remove the top item on peek
 * - should remove the top item on pop
 * - should not be full
 * - should add to the top on push
 * A Stack (full) 
 * - should be full
 * - should be non-empty
 * - should return the top item on peek
 * - should not remove the top item on peek
 * - should remove the top item on pop
 * - should complain on a push
 * 
 * 
 * 

 * One thing to keep in mind when using shared tests is that in ScalaTest, each test in a suite must have a unique name.
 * If you register the same tests repeatedly in the same suite, one problem you may encounter is an exception at runtime
 * complaining that multiple tests are being registered with the same test name. A good way to solve this problem in a AnyFlatSpec is to make sure
 * each invocation of a behavior function is in the context of a different set of when, verb (should,
 * must, or can), and that clauses,
 * which will prepend a string to each test name.
 * For example, the following code in a AnyFlatSpec would register a test with the name "A Stack (when empty) should be empty":
 * 
 *
 * 
 *   behavior of "A Stack (when empty)"
 *       
 *   it should "be empty" in {
 *     assert(emptyStack.empty)
 *   }
 *   // ...
 * 
 *
 * 

 * Or, using the shorthand notation:
 * 
 *
 * 
 *   "A Stack" when {
 *     "empty" should {
 *       "be empty" in {
 *         assert(emptyStack.empty)
 *       }
 *     }
 *   }
 *   // ...
 * 
 *
 * 

 * If the "should be empty" test was factored out into a behavior function, it could be called repeatedly so long
 * as each invocation of the behavior function is in the context of a different combination
 * of when, verb, and that clauses.
 * 
 *
 * @author Bill Venners
 */
@Finders(Array("org.scalatest.finders.FlatSpecFinder"))
open class AnyFlatSpec extends AnyFlatSpecLike {

  /**
   * Returns a user friendly string for this suite, composed of the
   * simple name of the class (possibly simplified further by removing dollar signs if added by the Scala interpeter) and, if this suite
   * contains nested suites, the result of invoking toString on each
   * of the nested suites, separated by commas and surrounded by parentheses.
   *
   * @return a user-friendly string for this suite
   */
  override def toString: String = Suite.suiteToString(None, this)
}