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/*
 * Copyright 2001-2008 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

import scala.collection.immutable.ListSet
import java.util.ConcurrentModificationException
import java.util.concurrent.atomic.AtomicReference
import org.scalatest.exceptions.StackDepthExceptionHelper.getStackDepth
import org.scalatest.events._
import Suite.anErrorThatShouldCauseAnAbort
import Suite.checkRunTestParamsForNull
import Suite.indentation
import verb.BehaveWord
import Suite.reportInfoProvided
import Suite.reportTestIgnored

/**
 * Trait that facilitates a “behavior-driven” style of development (BDD), in which tests
 * are combined with text that specifies the behavior the tests verify.
 * (Note: In BDD, the word example is usually used instead of test. The word test will not appear
 * in your code if you use WordSpec, so if you prefer the word example you can use it. However, in this documentation
 * the word test will be used, for clarity and to be consistent with the rest of ScalaTest.)
 * Here's an example FunSpec:
 *
 * 
 * import org.scalatest.FunSpec
 * import scala.collection.mutable.Stack
 *
 * class StackSpec extends FunSpec {
 *
 *   describe("A Stack") {
 *
 *     it("should pop values in last-in-first-out order") {
 *       val stack = new Stack[Int]
 *       stack.push(1)
 *       stack.push(2)
 *       assert(stack.pop() === 2)
 *       assert(stack.pop() === 1)
 *     }
 *
 *     it("should throw NoSuchElementException if an empty stack is popped") {
 *       val emptyStack = new Stack[String]
 *       intercept[NoSuchElementException] {
 *         emptyStack.pop()
 *       }
 *     }
 *   }
 * }
 * 
* *

* A FunSpec contains describe clauses and tests. You define a describe clause * with describe, and a test with it. Both * describe and it are methods, defined in * FunSpec, which will be invoked * by the primary constructor of StackSpec. * A describe clause names, or gives more information about, the subject (class or other entity) you are specifying * and testing. In the previous example, "A Stack" * is the subject under specification and test. With each test you provide a string (the spec text) that specifies * one bit of behavior of the subject, and a block of code that tests that behavior. * You place the spec text between the parentheses, followed by the test code between curly * braces. The test code will be wrapped up as a function passed as a by-name parameter to * it, which will register the test for later execution. *

* *

* A FunSpec'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 with the it method while the FunSpec is * in its registration phase. Any attempt to register a test after the FunSpec has * entered its ready phase, i.e., after run has been invoked on the FunSpec, * will be met with a thrown TestRegistrationClosedException. The recommended style * of using FunSpec 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. *

* *

* When you execute a FunSpec, it will send Formatters in the events it sends to the * Reporter. ScalaTest's built-in reporters will report these events in such a way * that the output is easy to read as an informal specification of the subject being tested. * For example, if you ran StackSpec from within the Scala interpreter: *

* *
 * scala> (new StackSpec).execute()
 * 
* *

* You would see: *

* *
 * A Stack
 * - should pop values in last-in-first-out order
 * - should throw NoSuchElementException if an empty stack is popped
 * 
* *

* Note: Trait FunSpec's syntax is in great part inspired by RSpec, a Ruby BDD framework. *

* *

* See also: Getting started with FunSpec. *

* *

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, FunSpec provides registration * methods that start with ignore instead of it. For example, to temporarily * disable the test with the name "should pop values in last-in-first-out order", just change “it” into “ignore,” like this: *

* *
 * import org.scalatest.FunSpec
 * import scala.collection.mutable.Stack
 *
 * class StackSpec extends FunSpec {
 *
 *   describe("A Stack") {
 *
 *     ignore("should pop values in last-in-first-out order") {
 *       val stack = new Stack[Int]
 *       stack.push(1)
 *       stack.push(2)
 *       assert(stack.pop() === 2)
 *       assert(stack.pop() === 1)
 *     }
 *
 *     it("should throw NoSuchElementException if an empty stack is popped") {
 *       val emptyStack = new Stack[String]
 *       intercept[NoSuchElementException] {
 *         emptyStack.pop()
 *       }
 *     }
 *   }
 * }
 * 
* *

* If you run this version of StackSpec with: *

* *
 * scala> (new StackSpec).execute()
 * 
* *

* It will run only the second test and report that the first test was ignored: *

* *
 * A Stack
 * - should pop values in last-in-first-out order !!! IGNORED !!!
 * - should throw NoSuchElementException if an empty stack is popped
 * 
* *

Informers

* *

* One of the parameters to the 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 FunSuite'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 one of its apply methods. * The Informer will then pass the information to the Reporter via an InfoProvided event. * Here's an example: *

* *
 * import org.scalatest.FunSpec
 *
 * class ExampleSpec extends FunSpec {
 *
 *   describe("The Scala language") {
 *
 *     it("should add correctly") {
 *       val sum = 1 + 1
 *       assert(sum === 2)
 *       info("Addition seems to work")
 *     }
 *
 *     it("should subtract correctly") {
 *       val diff = 7 - 2
 *       assert(diff === 5)
 *     }
 *   }
 * }
 * 
* * If you run this FunSpec from the interpreter, you will see the following message * included in the printed report: * *
 * ExampleSpec:
 * The Scala language
 * - should add correctly
 *   + Addition seems to work
 * - should subtract correctly 
 * 
* *

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, has not yet been implemented. *

* *

* You can mark a test as pending in FunSpec by placing "(pending)" after the * test name, like this: *

* *
 * import org.scalatest.FunSpec
 * import scala.collection.mutable.Stack
 *
 * class StackSpec extends FunSpec {
 *
 *   describe("A Stack") {
 *
 *     it("should pop values in last-in-first-out order") {
 *       val stack = new Stack[Int]
 *       stack.push(1)
 *       stack.push(2)
 *       assert(stack.pop() === 2)
 *       assert(stack.pop() === 1)
 *     }
 *
 *     it("should throw NoSuchElementException if an empty stack is popped") (pending)
 *   }
 * }
 * 
* *

* (Note: "(pending)" is the body of the test. Thus the test contains just one statement, an invocation * of the pending method, which throws TestPendingException.) * If you run this version of StackSpec with: *

* *
 * scala> (new StackSpec).execute()
 * 
* *

* It will run both tests, but report that the test named "A stack should pop values in last-in-first-out order" is pending. You'll see: *

* *
 * A Stack 
 * - should pop values in last-in-first-out order
 * - should throw NoSuchElementException if an empty stack is popped (pending)
 * 
* *

Tagging tests

* *

* A FunSpec's tests may be classified into groups by tagging them with string names. * As with any suite, when executing a FunSpec, groups of tests can * optionally be included and/or excluded. To tag a FunSpec's tests, * you pass objects that extend abstract class org.scalatest.Tag to the methods * that register tests, it and ignore. Class Tag takes one parameter, * a string name. If you have * created Java annotation interfaces for use as group names in direct subclasses of org.scalatest.Suite, * then you will probably want to use group names on your FunSpecs that match. To do so, simply * pass the fully qualified names of the Java interfaces to the Tag constructor. For example, if you've * defined Java annotation interfaces with fully qualified names, com.mycompany.tags.SlowTest and com.mycompany.tags.DbTest, then you could * create matching groups for FunSpecs like this: *

* *
 * import org.scalatest.Tag
 *
 * object SlowTest extends Tag("com.mycompany.tags.SlowTest")
 * object DbTest extends Tag("com.mycompany.tags.DbTest")
 * 
* *

* Given these definitions, you could place FunSpec tests into groups like this: *

* *
 * import org.scalatest.FunSpec
 *
 * class ExampleSpec extends FunSpec {
 *
 *   it("should add correctly", SlowTest) {
 *     val sum = 1 + 1
 *     assert(sum === 2)
 *   }
 *
 *   it("should subtract correctly", SlowTest, DbTest) {
 *     val diff = 4 - 1
 *     assert(diff === 3)
 *   }
 * }
 * 
* *

* This code marks both tests with the com.mycompany.tags.SlowTest tag, * and test "should subtract correctly" 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. *

* *

Shared fixtures

* *

* A test fixture is objects or other artifacts (such as files, sockets, database * connections, etc.) used by tests to do their work. * If a fixture is used by only one test method, then the definitions of the fixture objects can * be local to the method, such as the objects assigned to sum and diff in the * previous ExampleSpec examples. If multiple methods need to share an immutable fixture, one approach * is to assign them to instance variables. *

* *

* In some cases, however, shared mutable fixture objects may be changed by test methods such that * they need to be recreated or reinitialized before each test. Shared resources such * as files or database connections may also need to * be created and initialized before, and cleaned up after, each test. JUnit 3 offered methods setUp and * tearDown for this purpose. In ScalaTest, you can use the BeforeAndAfterEach trait, * which will be described later, to implement an approach similar to JUnit's setUp * and tearDown, however, this approach usually involves reassigning vars or mutating objects * between tests. Before going that route, you may wish to consider some more functional approaches that * avoid side effects. *

* *

Calling create-fixture methods

* *

* One approach is to write one or more create-fixture methods * that return a new instance of a needed fixture object (or an holder object containing multiple needed fixture objects) each time it * is called. You can then call a create-fixture method at the beginning of each * test method that needs the fixture, storing the returned object or objects in local variables. Here's an example: *

* *
 * import org.scalatest.FunSpec
 * import collection.mutable.ListBuffer
 *
 * class ExampleSpec extends FunSpec {
 * 
 *   def fixture =
 *     new {
 *       val builder = new StringBuilder("ScalaTest is ")
 *       val buffer = new ListBuffer[String]
 *     }
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       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") {
 *       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. *

* *

Instantiating fixture traits

* *

* A related technique is to place * the fixture objects in a fixture trait and run your test code in the context of a new anonymous class instance that mixes in * the fixture trait, like this: *

* *
 * import org.scalatest.FunSpec
 * import collection.mutable.ListBuffer
 * 
 * class ExampleSpec extends FunSpec {
 * 
 *   trait Fixture {
 *     val builder = new StringBuilder("ScalaTest is ")
 *     val buffer = new ListBuffer[String]
 *   }
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       new Fixture {
 *         builder.append("easy!")
 *         assert(builder.toString === "ScalaTest is easy!")
 *         assert(buffer.isEmpty)
 *         buffer += "sweet"
 *       }
 *     }
 * 
 *     it("should be fun") {
 *       new Fixture {
 *         builder.append("fun!")
 *         assert(builder.toString === "ScalaTest is fun!")
 *         assert(buffer.isEmpty)
 *       }
 *     }
 *   }
 * }
 * 
* *

Mixing in OneInstancePerTest

* *

* If every test method requires the same set of * mutable fixture objects, one other approach you can take is make them simply vals and mix in trait * OneInstancePerTest. If you mix in OneInstancePerTest, each test * will be run in its own instance of the Suite, similar to the way JUnit tests are executed. Here's an example: *

* *
 * import org.scalatest.FunSpec
 * import org.scalatest.OneInstancePerTest
 * import collection.mutable.ListBuffer
 * 
 * class ExampleSpec extends FunSpec with OneInstancePerTest {
 * 
 *   val builder = new StringBuilder("ScalaTest is ")
 *   val buffer = new ListBuffer[String]
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       builder.append("easy!")
 *       assert(builder.toString === "ScalaTest is easy!")
 *       assert(buffer.isEmpty)
 *       buffer += "sweet"
 *     }
 * 
 *     it("should be fun") {
 *       builder.append("fun!")
 *       assert(builder.toString === "ScalaTest is fun!")
 *       assert(buffer.isEmpty)
 *     }
 *   }
 * }
 * 
* *

* Although the create-fixture, fixture-trait, and OneInstancePerTest approaches take care of setting up a fixture before each * test, they don't address the problem of cleaning up a fixture after the test completes. In this situation, you'll need to either * use side effects or the loan pattern. *

* *

Mixing in BeforeAndAfter

* *

* One way to use side effects is to mix in the BeforeAndAfter trait. * 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: *

* *
 * import org.scalatest.FunSpec
 * import org.scalatest.BeforeAndAfter
 * import collection.mutable.ListBuffer
 * 
 * class ExampleSpec extends FunSpec with BeforeAndAfter {
 * 
 *   val builder = new StringBuilder
 *   val buffer = new ListBuffer[String]
 * 
 *   before {
 *     builder.append("ScalaTest is ")
 *   }
 * 
 *   after {
 *     builder.clear()
 *     buffer.clear()
 *   }
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       builder.append("easy!")
 *       assert(builder.toString === "ScalaTest is easy!")
 *       assert(buffer.isEmpty)
 *       buffer += "sweet"
 *     }
 * 
 *     it("should be fun") {
 *       builder.append("fun!")
 *       assert(builder.toString === "ScalaTest is fun!")
 *       assert(buffer.isEmpty)
 *     }
 *   }
 * }
 * 
* *

Overriding withFixture(NoArgTest)

* *

* An alternate way to take care of setup and cleanup via side effects * is to override withFixture. Trait Suite's implementation of * runTest, which is inherited by this trait, passes a no-arg test function to withFixture. It is withFixture's * responsibility to invoke that test function. Suite's implementation of withFixture simply * invokes the function, like this: *

* *
 * // Default implementation
 * protected def withFixture(test: NoArgTest) {
 *   test()
 * }
 * 
* *

* You can, therefore, override withFixture to perform setup before, and 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. * Here's an example: *

* *
 * import org.scalatest.FunSpec
 * import collection.mutable.ListBuffer
 *
 * class ExampleSpec extends FunSpec {
 *
 *   val builder = new StringBuilder
 *   val buffer = new ListBuffer[String]
 *
 *   override def withFixture(test: NoArgTest) {
 *     builder.append("ScalaTest is ") // perform setup
 *     try {
 *       test() // invoke the test function
 *     }
 *     finally {
 *       builder.clear() // perform cleanup
 *       buffer.clear()
 *     }
 *   }
 *
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       builder.append("easy!")
 *       assert(builder.toString === "ScalaTest is easy!")
 *       assert(buffer.isEmpty)
 *       buffer += "sweet"
 *     }
 *
 *     it("should be fun") {
 *       builder.append("fun!")
 *       assert(builder.toString === "ScalaTest is fun!")
 *       assert(buffer.isEmpty)
 *       buffer += "clear"
 *     }
 *   }
 * }
 * 
* *

* Note that the NoArgTest passed to withFixture, in addition to * an apply method that executes the test, also includes the test name as well as the config * map passed to runTest. Thus you can also use the test name and configuration objects in withFixture. *

* *

* The reason you should perform cleanup in a finally clause is that withFixture is called by * runTest, which expects an exception to be thrown to indicate a failed test. Thus when you invoke * the test function inside withFixture, it may complete abruptly with an exception. The finally * clause will ensure the fixture cleanup happens as that exception propagates back up the call stack to runTest. *

* *

Overriding withFixture(OneArgTest)

* *

* To use the loan pattern, you can extend org.scalatest.fixture.FunSpec (from the org.scalatest.fixture package) instead of * FunSpec. Each test in a org.scalatest.fixture.FunSpec 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. Here's an example: *

* *
 * import org.scalatest.fixture
 * import java.io.FileWriter
 * import java.io.File
 * 
 * class ExampleSpec extends fixture.FunSpec {
 * 
 *   final val tmpFile = "temp.txt"
 * 
 *   type FixtureParam = FileWriter
 * 
 *   def withFixture(test: OneArgTest) {
 * 
 *     val writer = new FileWriter(tmpFile) // set up the fixture
 *     try {
 *       test(writer) // "loan" the fixture to the test
 *     }
 *     finally {
 *       writer.close() // clean up the fixture
 *     }
 *   }
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") { writer =>
 *       writer.write("Hello, test!")
 *       writer.flush()
 *       assert(new File(tmpFile).length === 12)
 *     }
 * 
 *     it("should be fun") { writer =>
 *       writer.write("Hi, test!")
 *       writer.flush()
 *       assert(new File(tmpFile).length === 9)
 *     }
 *   }
 * }
 * 
* *

* For more information, see the documentation for org.scalatest.fixture.FunSpec. *

* *

Providing different fixtures to different tests

* *

* If different tests in the same FunSpec require different fixtures, you can combine the previous techniques and * provide each test with just the fixture or fixtures it needs. Here's an example in which a StringBuilder and a * ListBuffer are provided via fixture traits, and file writer (that requires cleanup) is provided via the loan pattern: *

* *
 * import java.io.FileWriter
 * import java.io.File
 * import collection.mutable.ListBuffer
 * import org.scalatest.FunSpec
 * 
 * class ExampleSpec extends FunSpec {
 * 
 *   final val tmpFile = "temp.txt"
 * 
 *   trait Builder {
 *     val builder = new StringBuilder("ScalaTest is ")
 *   }
 * 
 *   trait Buffer {
 *     val buffer = ListBuffer("ScalaTest", "is")
 *   }
 * 
 *   def withWriter(testCode: FileWriter => Any) {
 *     val writer = new FileWriter(tmpFile) // set up the fixture
 *     try {
 *       testCode(writer) // "loan" the fixture to the test
 *     }
 *     finally {
 *       writer.close() // clean up the fixture
 *     }
 *   }
 * 
 *   describe("Testing") {
 *
 *     it("should be productive") { // This test needs the StringBuilder fixture
 *       new Builder {
 *         builder.append("productive!")
 *         assert(builder.toString === "ScalaTest is productive!")
 *       }
 *     }
 * 
 *     it("should be readable") { // This test needs the ListBuffer[String] fixture
 *       new Buffer {
 *         buffer += ("readable!")
 *         assert(buffer === List("ScalaTest", "is", "readable!"))
 *       }
 *     }
 * 
 *     it("should be friendly") { // This test needs the FileWriter fixture
 *       withWriter { writer =>
 *         writer.write("Hello, user!")
 *         writer.flush()
 *         assert(new File(tmpFile).length === 12)
 *     }
 *   }
 * 
 *     it("should be clear and concise") { // This test needs the StringBuilder and ListBuffer
 *       new Builder with Buffer {
 *         builder.append("clear!")
 *         buffer += ("concise!")
 *         assert(builder.toString === "ScalaTest is clear!")
 *         assert(buffer === List("ScalaTest", "is", "concise!"))
 *       }
 *     }
 * 
 *     it("should be composable") { // This test needs all three fixtures
 *       new Builder with Buffer {
 *         builder.append("clear!")
 *         buffer += ("concise!")
 *         assert(builder.toString === "ScalaTest is clear!")
 *         assert(buffer === List("ScalaTest", "is", "concise!"))
 *         withWriter { writer =>
 *           writer.write(builder.toString)
 *           writer.flush()
 *           assert(new File(tmpFile).length === 19)
 *         }
 *       }
 *     }
 *   }
 * }
 * 
* *

* In the previous example, should be productive uses only the StringBuilder fixture, so it just instantiates * a new Builder, whereas should be readable uses only the ListBuffer fixture, so it just intantiates * a new Buffer. should be friendly needs just the FileWriter fixture, so it invokes * withWriter, which prepares and passes a FileWriter to the test (and takes care of closing it afterwords). *

* *

* Two tests need multiple fixtures: should be clear and concise needs both the StringBuilder and the * ListBuffer, so it instantiates a class that mixes in both fixture traits with new Builder with Buffer. * should be composable needs all three fixtures, so in addition to new Builder with Buffer it also invokes * withWriter, wrapping just the of the test code that needs the fixture. *

* *

* Note that in this case, the loan pattern is being implemented via the withWriter method that takes a function, not * by overriding org.scalatest.fixture.FunSpec's withFixture(OneArgTest) method. org.scalatest.fixture.FunSpec makes the most sense * if all (or at least most) tests need the same fixture, whereas in this Suite only two tests need the * FileWriter. *

* *

* In the previous example, the withWriter method passed an object into * the tests. Passing fixture objects into tests is generally a good idea when possible, but sometimes a side affect is unavoidable. * For example, if you need to initialize a database running on a server across a network, your with-fixture * method will likely have nothing to pass. In such cases, simply create a with-fixture method that takes a by-name parameter and * performs setup and cleanup via side effects, like this: *

* *
 * def withDataInDatabase(test: => Any) {
 *   // initialize the database across the network
 *   try {
 *     test // "loan" the initialized database to the test
 *   }
 *   finally {
 *     // clean up the database
 *   }
 * }
 * 
* *

* You can then use it like: *

* *
 * describe("A user") {
 *   it("should be able to log in") {
 *     withDataInDatabase {
 *       // test user logging in scenario
 *     }
 *   }
 * }
 * 
* *

Composing stackable fixture 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: *

* *
 * import org.scalatest.FunSpec
 * import org.scalatest.AbstractSuite
 * import collection.mutable.ListBuffer
 * 
 * trait Builder extends AbstractSuite { this: Suite =>
 *
 *   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 AbstractSuite { this: Suite =>
 *
 *   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 FunSpec with Builder with Buffer {
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       builder.append("easy!")
 *       assert(builder.toString === "ScalaTest is easy!")
 *       assert(buffer.isEmpty)
 *       buffer += "sweet"
 *     }
 * 
 *     it("should be fun") {
 *       builder.append("fun!")
 *       assert(builder.toString === "ScalaTest is fun!")
 *       assert(buffer.isEmpty)
 *       buffer += "clear"
 *     }
 *   }
 * }
 * 
* *

* By mixing in both the Builder and Buffer traits, ExampleSpec 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 FunSpec with Buffer with Builder
 * 
* *

* And if you only need one fixture you mix in only that trait: *

* *
 * class Example3Spec extends FunSpec 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: *

* *
 * import org.scalatest.FunSpec
 * import org.scalatest.BeforeAndAfterEach
 * 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 FunSpec with Builder with Buffer {
 * 
 *   describe("Testing") {
 *
 *     it("should be easy") {
 *       builder.append("easy!")
 *       assert(builder.toString === "ScalaTest is easy!")
 *       assert(buffer.isEmpty)
 *       buffer += "sweet"
 *     }
 * 
 *     it("should be fun") {
 *       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.afterAll throws an exception. *

* *

* One difference to bear in mind between the before-and-after traits and the withFixture methods, is that if * a withFixture method completes abruptly with an exception, it is considered a failed test. By contrast, if any of the * methods on the before-and-after traits (i.e., before and after of BeforeAndAfter, * beforeEach and afterEach of BeforeAndAfterEach, * and beforeAll and afterAll of BeforeAndAfterAll) complete abruptly, it is considered a * failed 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 FunSpec, you first place shared tests in behavior functions. These behavior functions will be * invoked during the construction phase of any FunSpec that uses them, so that the tests they contain will be registered as tests in that FunSpec. * 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 FunSpec 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 FunSpec that uses them. If they are shared * between different FunSpecs, however, you could also define them in a separate trait that is mixed into each FunSpec 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: FunSpec =>
 * 
 *   def nonEmptyStack(newStack: => Stack[Int], lastItemAdded: Int) {
 *
 *     it("should be non-empty") {
 *       assert(!newStack.empty)
 *     }
 *
 *     it("should return the top item on peek") {
 *       assert(newStack.peek === lastItemAdded)
 *     }
 *
 *     it("should not remove the top item on peek") {
 *       val stack = newStack
 *       val size = stack.size
 *       assert(stack.peek === lastItemAdded)
 *       assert(stack.size === size)
 *     }
 *
 *     it("should remove the top item on pop") {
 *       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") {
 *       assert(!newStack.full)
 *     }
 *
 *     it("should add to the top on push") {
 *       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 FunSpec 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 FunSpec 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
 * 
 *   describe("A Stack") {
 * 
 *     describe("(when empty)") {
 *       
 *       it("should be empty") {
 *         assert(emptyStack.empty)
 *       }
 * 
 *       it("should complain on peek") {
 *         intercept[IllegalStateException] {
 *           emptyStack.peek
 *         }
 *       }
 * 
 *       it("should complain on pop") {
 *         intercept[IllegalStateException] {
 *           emptyStack.pop
 *         }
 *       }
 *     }
 * 
 *     describe("(with one item)") {
 *       it should behave like nonEmptyStack(stackWithOneItem, lastValuePushed)
 *       it should behave like nonFullStack(stackWithOneItem)
 *     }
 *     
 *     describe("(with one item less than capacity)") {
 *       it should behave like nonEmptyStack(stackWithOneItemLessThanCapacity, lastValuePushed)
 *       it should behave like nonFullStack(stackWithOneItemLessThanCapacity)
 *     }
 * 
 *     describe("(full)") {
 *       
 *       it("should be full") {
 *         assert(fullStack.full)
 *       }
 * 
 *       it should behave like nonEmptyStack(fullStack, lastValuePushed)
 * 
 *       it("should complain on a push") {
 *         intercept[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> (new StackSpec).execute()
 * 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 FunSpec is to surround * each invocation of a behavior function with a describe clause, which will prepend a string to each test name. * For example, the following code in a FunSpec would register a test with the name "A Stack (when empty) should be empty": *

* *
 *   describe("A Stack") {
 * 
 *     describe("(when empty)") {
 *       
 *       it("should be empty") {
 *         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 inside a different set of describe clauses. * * @author Bill Venners */ trait FunSpec extends Suite { thisSuite => private final val engine = new Engine("concurrentSpecMod", "Spec") import engine._ private[scalatest] val sourceFileName = "FunSpec.scala" /** * Returns an Informer that during test execution will forward strings (and other objects) passed to its * apply method to the current reporter. If invoked in a constructor, it * will register the passed string for forwarding later during test execution. If invoked while this * FunSpec is being executed, such as from inside a test function, it will forward the information to * the current reporter immediately. If invoked at any other time, it will * throw an exception. This method can be called safely by any thread. */ implicit protected def info: Informer = atomicInformer.get /** * Class that, via an instance referenced from the it field, * supports test (and shared test) registration in FunSpecs. * *

* This class supports syntax such as the following test registration: *

* *
   * it("should be empty")
   * ^
   * 
* *

* and the following shared test registration: *

* *
   * it should behave like nonFullStack(stackWithOneItem)
   * ^
   * 
* *

* For more information and examples, see the main documentation for FunSpec. *

*/ protected class ItWord { /** * Register a test with the given spec text, optional tags, and test function value that takes no arguments. * An invocation of this method is called an “example.” * * This method will register the test for later execution via an invocation of one of the execute * methods. The name of the test will be a concatenation of the text of all surrounding describers, * from outside in, and the passed spec text, with one space placed between each item. (See the documenation * for testNames for an example.) The resulting test name must not have been registered previously on * this FunSpec instance. * * @param specText the specification text, which will be combined with the descText of any surrounding describers * to form the test name * @param testTags the optional list of tags for this test * @param testFun the test function * @throws DuplicateTestNameException if a test with the same name has been registered previously * @throws TestRegistrationClosedException if invoked after run has been invoked on this suite * @throws NullPointerException if specText or any passed test tag is null */ def apply(specText: String, testTags: Tag*)(testFun: => Unit) { registerTest(specText, testFun _, "itCannotAppearInsideAnotherIt", sourceFileName, "apply", 1, None, None, testTags: _*) } /** * Supports the registration of shared tests. * *

* This method supports syntax such as the following: *

* *
     * it should behave like nonFullStack(stackWithOneItem)
     *    ^
     * 
* *

* For examples of shared tests, see the Shared tests section * in the main documentation for trait FunSpec. *

*/ def should(behaveWord: BehaveWord) = behaveWord /** * Supports the registration of shared tests. * *

* This method supports syntax such as the following: *

* *
     * it must behave like nonFullStack(stackWithOneItem)
     *    ^
     * 
* *

* For examples of shared tests, see the Shared tests section * in the main documentation for trait FunSpec. *

*/ def must(behaveWord: BehaveWord) = behaveWord } /** * Supports test (and shared test) registration in FunSpecs. * *

* This field supports syntax such as the following: *

* *
   * it("should be empty")
   * ^
   * 
* *
 class="stExamples"
   * it should behave like nonFullStack(stackWithOneItem)
   * ^
   * 
* *

* For more information and examples of the use of the it field, see the main documentation for this trait. *

*/ protected val it = new ItWord /** * Class that, via an instance referenced from the they field, * supports test (and shared test) registration in FunSpecs. * *

* This class supports syntax such as the following test registration: *

* *
   * they("should be empty")
   * ^
   * 
* *

* and the following shared test registration: *

* *
   * they should behave like nonFullStack(stackWithOneItem)
   * ^
   * 
* *

* For more information and examples, see the main documentation for FunSpec. *

*/ protected class TheyWord { /** * Register a test with the given spec text, optional tags, and test function value that takes no arguments. * An invocation of this method is called an “example.” * * This method will register the test for later execution via an invocation of one of the execute * methods. The name of the test will be a concatenation of the text of all surrounding describers, * from outside in, and the passed spec text, with one space placed between each item. (See the documenation * for testNames for an example.) The resulting test name must not have been registered previously on * this FunSpec instance. * * @param specText the specification text, which will be combined with the descText of any surrounding describers * to form the test name * @param testTags the optional list of tags for this test * @param testFun the test function * @throws DuplicateTestNameException if a test with the same name has been registered previously * @throws TestRegistrationClosedException if invoked after run has been invoked on this suite * @throws NullPointerException if specText or any passed test tag is null */ def apply(specText: String, testTags: Tag*)(testFun: => Unit) { registerTest(specText, testFun _, "theyCannotAppearInsideAnotherThey", sourceFileName, "apply", 1, None, None, testTags: _*) } /** * Supports the registration of shared tests. * *

* This method supports syntax such as the following: *

* *
     * they should behave like nonFullStack(stackWithOneItem)
     *      ^
     * 
* *

* For examples of shared tests, see the Shared tests section * in the main documentation for trait FunSpec. *

*/ def should(behaveWord: BehaveWord) = behaveWord /** * Supports the registration of shared tests. * *

* This method supports syntax such as the following: *

* *
     * they must behave like nonFullStack(stackWithOneItem)
     *      ^
     * 
* *

* For examples of shared tests, see the Shared tests section * in the main documentation for trait FunSpec. *

*/ def must(behaveWord: BehaveWord) = behaveWord } /** * Supports test (and shared test) registration in FunSpecs. * *

* This field supports syntax such as the following: *

* *
   * they("should be empty")
   * ^
   * 
* *
 class="stExamples"
   * it should behave like nonFullStack(stackWithOneItem)
   * ^
   * 
* *

* For more information and examples of the use of the it field, see the main documentation for this trait. *

*/ protected val they = new TheyWord /** * Register a test to ignore, which has the given spec text, optional tags, and test function value that takes no arguments. * This method will register the test for later ignoring via an invocation of one of the execute * methods. This method exists to make it easy to ignore an existing test by changing the call to it * to ignore without deleting or commenting out the actual test code. The test will not be executed, but a * report will be sent that indicates the test was ignored. The name of the test will be a concatenation of the text of all surrounding describers, * from outside in, and the passed spec text, with one space placed between each item. (See the documenation * for testNames for an example.) The resulting test name must not have been registered previously on * this FunSpec instance. * * @param testText the specification text, which will be combined with the descText of any surrounding describers * to form the test name * @param testTags the optional list of tags for this test * @param testFun the test function * @throws DuplicateTestNameException if a test with the same name has been registered previously * @throws TestRegistrationClosedException if invoked after run has been invoked on this suite * @throws NullPointerException if specText or any passed test tag is null */ protected def ignore(testText: String, testTags: Tag*)(testFun: => Unit) { registerIgnoredTest(testText, testFun _, "ignoreCannotAppearInsideAnIt", sourceFileName, "ignore", 1, testTags: _*) } /** * Describe a “subject” being specified and tested by the passed function value. The * passed function value may contain more describers (defined with describe) and/or tests * (defined with it). This trait's implementation of this method will register the * description string and immediately invoke the passed function. */ protected def describe(description: String)(fun: => Unit) { registerNestedBranch(description, None, fun, "describeCannotAppearInsideAnIt", sourceFileName, "describe", 1) } /** * An immutable Set of test names. If this FunSpec contains no tests, this method returns an * empty Set. * *

* This trait's implementation of this method will return a set that contains the names of all registered tests. The set's * iterator will return those names in the order in which the tests were registered. Each test's name is composed * of the concatenation of the text of each surrounding describer, in order from outside in, and the text of the * example itself, with all components separated by a space. For example, consider this FunSpec: *

* *
   * import org.scalatest.FunSpec
   *
   * class StackSpec extends FunSpec {
   *   describe("A Stack") {
   *     describe("(when not empty)") {
   *       it("must allow me to pop") {}
   *     }
   *     describe("(when not full)") {
   *       it("must allow me to push") {}
   *     }
   *   }
   * }
   * 
* *

* Invoking testNames on this FunSpec will yield a set that contains the following * two test name strings: *

* *
   * "A Stack (when not empty) must allow me to pop"
   * "A Stack (when not full) must allow me to push"
   * 
*/ override def testNames: Set[String] = { // I'm returning a ListSet here so that they tests will be run in registration order ListSet(atomic.get.testNamesList.toArray: _*) } /** * Run a test. This trait's implementation runs the test registered with the name specified by * testName. Each test's name is a concatenation of the text of all describers surrounding a test, * from outside in, and the test's spec text, with one space placed between each item. (See the documenation * for testNames for an example.) * * @param testName the name of one test to execute. * @param reporter the Reporter to which results will be reported * @param stopper the Stopper that will be consulted to determine whether to stop execution early. * @param configMap a Map of properties that can be used by this FunSpec's executing tests. * @throws NullPointerException if any of testName, reporter, stopper, or configMap * is null. */ protected override def runTest(testName: String, reporter: Reporter, stopper: Stopper, configMap: Map[String, Any], tracker: Tracker) { def invokeWithFixture(theTest: TestLeaf) { val theConfigMap = configMap withFixture( new NoArgTest { def name = testName def apply() { theTest.testFun() } def configMap = theConfigMap } ) } runTestImpl(thisSuite, testName, reporter, stopper, configMap, tracker, true, invokeWithFixture) } /** * A Map whose keys are String tag names to which tests in this FunSpec belong, and values * the Set of test names that belong to each tag. If this FunSpec contains no tags, this method returns an empty Map. * *

* This trait's implementation returns tags that were passed as strings contained in Tag objects passed to * methods test and ignore. *

*/ override def tags: Map[String, Set[String]] = atomic.get.tagsMap /** * Run zero to many of this FunSpec's tests. * * @param testName an optional name of one test to run. If None, all relevant tests should be run. * I.e., None acts like a wildcard that means run all relevant tests in this Suite. * @param reporter the Reporter to which results will be reported * @param stopper the Stopper that will be consulted to determine whether to stop execution early. * @param filter a Filter with which to filter tests based on their tags * @param configMap a Map of key-value pairs that can be used by the executing Suite of tests. * @param distributor an optional Distributor, into which to put nested Suites to be run * by another entity, such as concurrently by a pool of threads. If None, nested Suites will be run sequentially. * @param tracker a Tracker tracking Ordinals being fired by the current thread. * @throws NullPointerException if any of the passed parameters is null. * @throws IllegalArgumentException if testName is defined, but no test with the specified test name * exists in this Suite */ protected override def runTests(testName: Option[String], reporter: Reporter, stopper: Stopper, filter: Filter, configMap: Map[String, Any], distributor: Option[Distributor], tracker: Tracker) { runTestsImpl(thisSuite, testName, reporter, stopper, filter, configMap, distributor, tracker, info, true, runTest) } override def run(testName: Option[String], reporter: Reporter, stopper: Stopper, filter: Filter, configMap: Map[String, Any], distributor: Option[Distributor], tracker: Tracker) { runImpl(thisSuite, testName, reporter, stopper, filter, configMap, distributor, tracker, super.run) } /** * Supports shared test registration in FunSpecs. * *

* This field supports syntax such as the following: *

* *
   * it should behave like nonFullStack(stackWithOneItem)
   *           ^
   * 
* *

* For more information and examples of the use of behave, see the Shared tests section * in the main documentation for this trait. *

*/ protected val behave = new BehaveWord /** * Suite style name. */ final override val styleName: String = "org.scalatest.FunSpec" }




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