Package com.google.errorprone

Class CompilationTestHelper

java.lang.Object

com.google.errorprone.CompilationTestHelper

@CheckReturnValue
public class CompilationTestHelper
extends Object

Helps test Error Prone bug checkers and compilations.

Method Summary

Modifier and Type	Method	Description
CompilationTestHelper	addModules(String... modules)
CompilationTestHelper	addSourceFile(String path)	Adds a source file to the test compilation, from an existing resource file.
CompilationTestHelper	addSourceLines(String path, String... lines)	Adds a source file to the test compilation, from the string content of the file.
void	doTest()	Performs a compilation and checks that the diagnostics and result match the expectations.
CompilationTestHelper	expectErrorMessage(String key, com.google.common.base.Predicate<? super String> matcher)	Expects an error message matching matcher at the line below a comment matching the key.
CompilationTestHelper	expectNoDiagnostics()	Tells the compilation helper to expect that no diagnostics will be generated, even if the source file contains bug markers.
CompilationTestHelper	expectResult(com.sun.tools.javac.main.Main.Result result)	Tells the compilation helper to expect a specific result from the compilation, e.g.
CompilationTestHelper	matchAllDiagnostics()	By default, the compilation helper will only inspect diagnostics generated by the check being tested.
static CompilationTestHelper	newInstance(ScannerSupplier scannerSupplier, Class<?> clazz)	Returns a new CompilationTestHelper.
static CompilationTestHelper	newInstance(Class<? extends BugChecker> checker, Class<?> clazz)	Returns a new CompilationTestHelper.
CompilationTestHelper	setArgs(String... args)	Sets custom command-line arguments for the compilation.
CompilationTestHelper	setArgs(List<String> args)	Sets custom command-line arguments for the compilation.
CompilationTestHelper	withClasspath(Class<?>... classes)	Sets the classpath for the test compilation, overriding the default of using the runtime classpath of the test execution.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

newInstance

public static CompilationTestHelper newInstance(ScannerSupplier scannerSupplier,
                                                Class<?> clazz)

Returns a new CompilationTestHelper.

Parameters:

scannerSupplier - the ScannerSupplier to test

clazz - the class to use to locate file resources

newInstance

public static CompilationTestHelper newInstance(Class<? extends BugChecker> checker,
                                                Class<?> clazz)

Returns a new CompilationTestHelper.

Parameters:

checker - the BugChecker to test

clazz - the class to use to locate file resources

addSourceLines

public CompilationTestHelper addSourceLines(String path,
                                            String... lines)

Adds a source file to the test compilation, from the string content of the file.

The diagnostics expected from compiling the file are inferred from the file contents. For each line of the test file that contains the bug marker pattern "// BUG: Diagnostic contains: foo", we expect to see a diagnostic on that line containing "foo". For each line of the test file that does not contain the bug marker pattern, we expect no diagnostic to be generated. You can also use "// BUG: Diagnostic matches: X" in tandem with expectErrorMessage("X", "foo") to allow you to programmatically construct the error message.

Parameters:

path - a path for the source file

lines - the content of the source file

addSourceFile

public CompilationTestHelper addSourceFile(String path)

Adds a source file to the test compilation, from an existing resource file.

See addSourceLines(java.lang.String, java.lang.String...) for how expected diagnostics should be specified.

Parameters:

path - the path to the source file

withClasspath

public CompilationTestHelper withClasspath(Class<?>... classes)

Sets the classpath for the test compilation, overriding the default of using the runtime classpath of the test execution. This is useful to verify correct behavior when the classpath is incomplete.

Parameters:

classes - the class(es) to use as the classpath

addModules

public CompilationTestHelper addModules(String... modules)

setArgs

public CompilationTestHelper setArgs(String... args)

Sets custom command-line arguments for the compilation. These will be appended to the default compilation arguments.

setArgs

public CompilationTestHelper setArgs(List<String> args)

Sets custom command-line arguments for the compilation. These will be appended to the default compilation arguments.

expectNoDiagnostics

public CompilationTestHelper expectNoDiagnostics()

Tells the compilation helper to expect that no diagnostics will be generated, even if the source file contains bug markers. Useful for testing that a check is actually disabled when the proper command-line argument is passed.

matchAllDiagnostics

public CompilationTestHelper matchAllDiagnostics()

By default, the compilation helper will only inspect diagnostics generated by the check being tested. This behaviour can be disabled to test the interaction between Error Prone checks and javac diagnostics.

expectResult

public CompilationTestHelper expectResult(com.sun.tools.javac.main.Main.Result result)

Tells the compilation helper to expect a specific result from the compilation, e.g. success or failure.

expectErrorMessage

public CompilationTestHelper expectErrorMessage(String key,
                                                com.google.common.base.Predicate<? super String> matcher)

Expects an error message matching matcher at the line below a comment matching the key. For example, given the source

   // BUG: Diagnostic matches: X
   a = b + c;
 

... you can use expectErrorMessage("X", Predicates.containsPattern("Can't add b to c"));

Error message keys that don't match any diagnostics will cause test to fail.

doTest

public void doTest()

Performs a compilation and checks that the diagnostics and result match the expectations.