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package org.tudalgo.algoutils.student.test;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Predicate;
/**
* Utility class for tests written by students.
*/
public class StudentTestUtils {
/**
* The {@link PrintStream} to use for test output.
*/
public static PrintStream S_TEST_OUT = System.out;
/**
* The {@link PrintStream} to use for test error output.
*/
public static PrintStream S_TEST_ERR = System.err;
/**
* The list of all {@linkplain StudentTestResult test results} created by the student tests.
*/
public static List> testResults = new ArrayList<>();
/**
* Utility method to create a {@link StudentTest} with the given {@code predicate} and {@code messageProvider} and
* apply it to the given {@code toTest} value. The result is added to {@link #testResults}.
*
* @param toTest the value to test
* @param predicate the predicate to test the value with
* @param messageProvider the message provider to create the message for the result
* @param the type of the value to test
*/
private static void simpleStudentTest(
T toTest,
Predicate predicate,
StudentTestResultMessageProvider messageProvider
) {
var test = new StudentTest<>(predicate, messageProvider);
final var result = test.test(toTest);
testResults.add(result);
if (result.hasFailed()) {
S_TEST_ERR.println(result.message());
result.throwable().printStackTrace(S_TEST_ERR);
}
}
/**
* Checks that the given {@code expected} value is equal to the given {@code actual} value.
* If the values are not equal, an error message is printed to {@link #S_TEST_ERR}.
*
* This method is intended to be used in the context of a test case from the student.
*
*
Example:
*
{@code
* public static int max(int a, int b) {
* return a > b ? a : b;
* }
* public static void main(String[] args) {
* testEquals(3, max(2, 3));
* testEquals(3, max(3, 2));
* testEquals(3, max(3, 3));
* }
* }
*
* @param expected the expected value
* @param actual the actual value
*/
public static void testEquals(Object expected, Object actual) {
simpleStudentTest(
actual,
a -> a.equals(expected),
r -> String.format("Expected: <%s>, but was: <%s>", expected, r.toTest())
);
}
/**
* Checks that the given {@code actual} value is in the range {@code [min, max]}. The range is inclusive.
* If the value is not in the range, an error message is printed to {@link #S_TEST_ERR}.
*
* This method is intended to be used in the context of a test case from the student.
*
*
Example:
*
{@code
* public static void main(String[] args) {
* testWithinRange(0, 10, 5);
* testWithinRange(0, 10, 0);
* testWithinRange(0, 10, 10);
* testWithinRange(0, 10, -1); // will print an error message
* }
* }
*
* @param min the minimum value of the range
* @param max the maximum value of the range
* @param actual the actual value
*/
public static > void testWithinRange(T min, T max, T actual) {
simpleStudentTest(
actual,
a -> a.compareTo(min) >= 0 && a.compareTo(max) <= 0,
r -> String.format("Expected: <%s> to be in range <%s, %s>, but was not", actual, min, max)
);
}
/**
* Checks that the given {@code actual} value is in the range {@code [min, max]}. The range is inclusive.
* If the value is not in the range, an error message is printed to {@link #S_TEST_ERR}.
*
* This method is intended to be used in the context of a test case from the student.
*
*
Example:
*
{@code
* public static void main(String[] args) {
* testWithinRange(0, 10, 5);
* testWithinRange(0, 10, 0);
* testWithinRange(0, 10, 10);
* testWithinRange(0, 10, -1); // will print an error message
* }
* }
*
* @param min the minimum value of the range
* @param max the maximum value of the range
* @param actual the actual value
*/
public static void testWithinRange(double min, double max, double actual) {
testWithinRange(Double.valueOf(min), Double.valueOf(max), Double.valueOf(actual));
}
/**
* Checks if the given task throws an exception.
* If no exception is thrown or the task throws an exception to the wrong type, an error message is printed to
* {@link #S_TEST_ERR}.
*
* This method is intended to be used in the context of a test case from the student.
*
* @param expectedType the expected type of the exception
* @param task the task to execute
* @param the type of the exception to check
*/
public static void testThrows(Class expectedType, Task task) {
simpleStudentTest(null, r -> {
try {
task.execute();
// If no exception was thrown, it's an error
return false;
} catch (Throwable throwable) {
// Check if the thrown error matches the expected type
if (expectedType.isInstance(throwable)) {
return true;
} else {
throw new IllegalStateException(throwable);
}
}
}, result -> "Expected exception %s to be thrown, but got %s".formatted(expectedType.getName(),
result.hasFailedWithException() ? result.throwable().getCause().getClass().getName() : "none"));
}
/**
* Prints a summary of the test results to {@link #S_TEST_OUT}.
* The summary contains the number of passed and failed tests.
*
* This method is intended to be used in the context of a test case from the student.
* Ideally, it is called at the end of the {@code main} method.
*/
public static void printTestResults() {
final var passed = testResults.stream().filter(StudentTestResult::hasPassed).count();
final var failedByAssertion = testResults.stream().filter(StudentTestResult::hasFailedByAssertion).count();
final var failedWithException = testResults.stream().filter(StudentTestResult::hasFailedWithException).count();
final var failed = failedByAssertion + failedWithException;
final StringBuilder messageBuilder = new StringBuilder();
if (failed == 0) {
messageBuilder.append(String.format("All %s test(s) passed!%n", passed));
} else {
messageBuilder.append(String.format("%s of %s total test(s) passed!%n", passed, testResults.size()));
if (failedByAssertion > 0) {
messageBuilder.append(String.format(" %s test(s) were executed, but failed by assertion.%n", failedByAssertion));
}
if (failedWithException > 0) {
messageBuilder.append(String.format(" %s test(s) threw an exception during execution.%n", failedWithException));
}
}
final var message = messageBuilder.toString();
// get length of longest line
final var longestLine = message.lines().mapToInt(String::length).max().orElse("Test results summary".length());
// print header
S_TEST_OUT.println("=".repeat(longestLine));
S_TEST_OUT.println("Test results summary");
S_TEST_OUT.println("-".repeat(longestLine));
S_TEST_OUT.print(message);
// print footer
S_TEST_OUT.println("=".repeat(longestLine));
}
}