Package: org.gradle.testkit.runner

## [Java] Class GradleRunner

- org.gradle.testkit.runner.GradleRunner

- Executes a Gradle build, allowing inspection of the outcome.

  A Gradle runner can be used to functionally test build logic, by executing a contrived build. Assertions can then be made on the outcome of the build, such as the state of files created by the build, or what tasks were actually executed during the build.

  A runner can be created via the create() method.

  Typically, the test code using the runner will programmatically create a build (e.g. by writing Gradle build files to a temporary space) to execute. The build to execute is effectively specified by the withProjectDir(File)} method. It is a requirement that a project directory be set.

  The withArguments(String...) method allows the build arguments to be specified, just as they would be on the command line.

  The build() method can be used to invoke the build when it is expected to succeed, while the buildAndFail() method can be used when the build is expected to fail.

  GradleRunner instances are not thread safe and cannot be used concurrently. However, multiple instances are able to be used concurrently.

  Please see the Gradle TestKit User Guide chapter for more information.

  Since:
    2.6

- - ### Methods Summary

    Methods
    Type | Name and description
    --- | ---
    `BuildResult` | `build()` Executes a build, expecting it to complete without failure.
    `BuildResult` | `buildAndFail()` Executes a build, expecting it to complete with failure.
    `static GradleRunner` | `create()` Creates a new Gradle runner.
    `GradleRunner` | `forwardOutput()` Forwards the output of executed builds to the System.out stream.
    `GradleRunner` | `forwardStdError(Writer writer)` Configures the runner to forward standard error output from builds to the given writer.
    `GradleRunner` | `forwardStdOutput(Writer writer)` Configures the runner to forward standard output from builds to the given writer.
    `List<String>` | `getArguments()` The build arguments.
    `List<? extends File>` | `getPluginClasspath()` The injected plugin classpath for the build.
    `File` | `getProjectDir()` The directory that the build will be executed in.
    `boolean` | `isDebug()` Indicates whether the build should be executed “in process” so that it is debuggable.
    `GradleRunner` | `withArguments(List<String> arguments)` Sets the build arguments.
    `GradleRunner` | `withArguments(String... arguments)` Sets the build arguments.
    `GradleRunner` | `withDebug(boolean flag)` Sets whether debugging support is enabled.
    `GradleRunner` | `withGradleDistribution(URI distribution)` Configures the runner to execute the build using the distribution of Gradle specified.
    `GradleRunner` | `withGradleInstallation(File installation)` Configures the runner to execute the build using the installation of Gradle specified.
    `GradleRunner` | `withGradleVersion(String versionNumber)` Configures the runner to execute the build with the version of Gradle specified.
    `GradleRunner` | `withPluginClasspath()` Sets the plugin classpath based on the Gradle plugin development plugin conventions.
    `GradleRunner` | `withPluginClasspath(Iterable<? extends File> classpath)` Sets the injected plugin classpath for the build.
    `GradleRunner` | `withProjectDir(File projectDir)` Sets the directory that the Gradle will be executed in.
    `GradleRunner` | `withTestKitDir(File testKitDir)` Sets the directory to use for TestKit's working storage needs.

  - ### Inherited Methods Summary

    Inherited Methods
    Methods inherited from class | Name
    --- | ---
    `class Object` | `wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll`

- - ### Method Detail

    - #### public BuildResult build()

      Executes a build, expecting it to complete without failure.

      throws:
        InvalidRunnerConfigurationException if the configuration of this runner is invalid (e.g. project directory not set)
      throws:
        UnexpectedBuildFailure if the build does not succeed
      Returns:
        the build result

    - #### public BuildResult buildAndFail()

      Executes a build, expecting it to complete with failure.

      throws:
        InvalidRunnerConfigurationException if the configuration of this runner is invalid (e.g. project directory not set)
      throws:
        UnexpectedBuildSuccess if the build succeeds
      Returns:
        the build result

    - #### public static GradleRunner create()

      Creates a new Gradle runner.

      The runner requires a Gradle distribution (and therefore a specific version of Gradle) in order to execute builds. This method will find a Gradle distribution, based on the filesystem location of this class. That is, it is expected that this class is loaded from a Gradle distribution.

      When using the runner as part of tests being executed by Gradle (i.e. a build using the `gradleTestKit()` dependency), this means that the same distribution of Gradle that is executing the tests will be used by runner returned by this method.

      When using the runner as part of tests being executed by an IDE, this means that the same distribution of Gradle that was used when importing the project will be used.

      Returns:
        a new Gradle runner

    - #### public GradleRunner forwardOutput()

      Forwards the output of executed builds to the System.out stream.

      The output of the build is always available via BuildResult.getOutput. This method can be used to additionally forward the output to `System.out` of the process using the runner.

      This method does not separate the standard output and error output. The two streams will be merged as they typically are when using Gradle from a command line interface. If you require separation of the streams, you can use forwardStdOutput(Writer) and forwardStdError(Writer) directly.

      Calling this method will negate the effect of previously calling forwardStdOutput(Writer) and/or forwardStdError(Writer).

      Returns:
        this
      See Also:
        forwardStdOutput(Writer)
        forwardStdError(Writer)
      Since:
        2.9

    - #### public GradleRunner forwardStdError(Writer writer)

      Configures the runner to forward standard error output from builds to the given writer.

      The output of the build is always available via BuildResult.getOutput. This method can be used to additionally capture the error output.

      Calling this method will negate the effect of previously calling forwardOutput().

      The given writer will not be closed by the runner.

      Parameters:
        `writer` - the writer that build standard error output should be forwarded to
      Returns:
        this
      See Also:
        forwardOutput()
        forwardStdOutput(Writer)
      Since:
        2.9

    - #### public GradleRunner forwardStdOutput(Writer writer)

      Configures the runner to forward standard output from builds to the given writer.

      The output of the build is always available via BuildResult.getOutput. This method can be used to additionally capture the output.

      Calling this method will negate the effect of previously calling forwardOutput().

      The given writer will not be closed by the runner.

      When executing builds with Gradle versions earlier than 2.9 in debug mode, any output produced by the build that was written directly to `System.out` or `System.err` will not be represented in BuildResult.getOutput. This is due to a defect that was fixed in Gradle 2.9.

      Parameters:
        `writer` - the writer that build standard output should be forwarded to
      Returns:
        this
      See Also:
        forwardOutput()
        forwardStdError(Writer)
      Since:
        2.9

    - #### public List<String> getArguments()

      The build arguments.

      Effectively, the command line arguments to Gradle. This includes all tasks, flags, properties etc.

      The returned list is immutable.

      Returns:
        the build arguments

    - #### public List<? extends File> getPluginClasspath()

      The injected plugin classpath for the build.

      The returned list is immutable. Returns an empty list if no classpath was provided with withPluginClasspath(Iterable).

      Returns:
        the classpath of plugins to make available to the build under test
      Since:
        2.8

    - #### public File getProjectDir()

      The directory that the build will be executed in.

      This is analogous to the current directory when executing Gradle from the command line.

      Returns:
        the directory to execute the build in

    - #### public boolean isDebug()

      Indicates whether the build should be executed “in process” so that it is debuggable.

      If debug support is not enabled, the build will be executed in an entirely separate process. This means that any debugger that is attached to the test execution process will not be attached to the build process. When debug support is enabled, the build is executed in the same process that is using the Gradle Runner, allowing the build to be debugged.

      Debug support is off (i.e. `false`) by default. It can be enabled by setting the system property `org.gradle.testkit.debug` to `true` for the test process, or by using the withDebug(boolean) method.

      Returns:
        whether the build should be executed in the same process
      Since:
        2.9

    - #### public GradleRunner withArguments(List<String> arguments)

      Sets the build arguments.

      Parameters:
        `arguments` - the build arguments
      Returns:
        this
      See Also:
        getArguments()

    - #### public GradleRunner withArguments(String... arguments)

      Sets the build arguments.

      Parameters:
        `arguments` - the build arguments
      Returns:
        this
      See Also:
        getArguments()

    - #### public GradleRunner withDebug(boolean flag)

      Sets whether debugging support is enabled.

      Parameters:
        `flag` - the debug flag
      Returns:
        this
      See Also:
        isDebug()
      Since:
        2.9

    - #### public GradleRunner withGradleDistribution(URI distribution)

      Configures the runner to execute the build using the distribution of Gradle specified.

      The given URI must point to a valid Gradle distribution ZIP file. This method is typically used as an alternative to withGradleVersion(String), where it is preferable to obtain the Gradle runtime from “local” servers.

      Unless previously downloaded, this method will cause the Gradle runtime at the given URI to be downloaded. The download will be cached beneath the Gradle User Home directory, the location of which is determined by the following in order of precedence:

      1. The system property `"gradle.user.home"`
      2. The environment variable `"GRADLE_USER_HOME"`

      If neither are present, `"~/.gradle"` will be used, where `"~"` is the value advertised by the JVM's `"user.dir"` system property. The system property and environment variable are read in the process using the runner, not the build process.

      Parameters:
        `distribution` - a URI pointing at a valid Gradle distribution zip file
      Returns:
        this
      See Also:
        withGradleVersion(String)
        withGradleInstallation(File)
      Since:
        2.9

    - #### public GradleRunner withGradleInstallation(File installation)

      Configures the runner to execute the build using the installation of Gradle specified.

      The given file must be a directory containing a valid Gradle installation.

      Alternatively, you may use withGradleVersion(String) to use an automatically installed Gradle version.

      Parameters:
        `installation` - a valid Gradle installation
      Returns:
        this
      See Also:
        withGradleVersion(String)
        withGradleDistribution(URI)
      Since:
        2.9

    - #### public GradleRunner withGradleVersion(String versionNumber)

      Configures the runner to execute the build with the version of Gradle specified.

      Unless previously downloaded, this method will cause the Gradle runtime for the version specified to be downloaded over the Internet from Gradle's distribution servers. The download will be cached beneath the Gradle User Home directory, the location of which is determined by the following in order of precedence:

      1. The system property `"gradle.user.home"`
      2. The environment variable `"GRADLE_USER_HOME"`

      If neither are present, `"~/.gradle"` will be used, where `"~"` is the value advertised by the JVM's `"user.dir"` system property. The system property and environment variable are read in the process using the runner, not the build process.

      Alternatively, you may use withGradleInstallation(File) to use an installation already on the filesystem.

      To use a non standard Gradle runtime, or to obtain the runtime from an alternative location, use withGradleDistribution(URI).

      Parameters:
        `versionNumber` - the version number (e.g. "2.9")
      Returns:
        this
      See Also:
        withGradleInstallation(File)
        withGradleDistribution(URI)
      Since:
        2.9

    - #### public GradleRunner withPluginClasspath()

      Sets the plugin classpath based on the Gradle plugin development plugin conventions.

      The 'java-gradle-plugin' generates a file describing the plugin under test and makes it available to the test runtime. This method configures the runner to use this file. Please consult the Gradle documentation of this plugin for more information.

      This method looks for a file named `plugin-under-test-metadata.properties` on the runtime classpath, and uses the `implementation-classpath` as the classpath, which is expected to a File.pathSeparatorChar joined string. If the plugin metadata file cannot be resolved an InvalidPluginMetadataException is thrown.

      Plugins from classpath are able to be resolved using the `plugins { }` syntax in the build under test. Please consult the TestKit Gradle User Guide chapter for more information and usage examples.

      Calling this method will replace any previous classpath specified via withPluginClasspath(Iterable) and vice versa.

      Note: this method will cause an InvalidRunnerConfigurationException to be emitted when the build is executed, if the version of Gradle executing the build (i.e. not the version of the runner) is earlier than Gradle 2.8 as those versions do not support this feature. Please consult the TestKit Gradle User Guide chapter alternative strategies that can be used for older Gradle versions.

      Returns:
        this
      See Also:
        withPluginClasspath(Iterable)
        getPluginClasspath()
      Since:
        2.13

    - #### public GradleRunner withPluginClasspath(Iterable<? extends File> classpath)

      Sets the injected plugin classpath for the build.

      Plugins from the given classpath are able to be resolved using the `plugins { }` syntax in the build under test. Please consult the TestKit Gradle User Guide chapter for more information and usage examples.

      Note: this method will cause an InvalidRunnerConfigurationException to be emitted when the build is executed, if the version of Gradle executing the build (i.e. not the version of the runner) is earlier than Gradle 2.8 as those versions do not support this feature. Please consult the TestKit Gradle User Guide chapter alternative strategies that can be used for older Gradle versions.

      Parameters:
        `classpath` - the classpath of plugins to make available to the build under test
      Returns:
        this
      See Also:
        getPluginClasspath()
      Since:
        2.8

    - #### public GradleRunner withProjectDir(File projectDir)

      Sets the directory that the Gradle will be executed in.

      This is typically set to the root project of the build under test.

      A project directory must be set. This method must be called before build() or buildAndFail().

      All builds executed with the runner effectively implicitly add the `--no-search-upwards` argument. This suppresses Gradle's default behaviour of searching upwards through the file system in order to find the root of the current project tree. This default behaviour is often utilised when focusing on a particular build within a multi-project build. This behaviour is suppressed due to test builds being executed potentially being created within a “real build” (e.g. under the `/build` directory of the plugin's project directory).

      Parameters:
        `projectDir` - the project directory
      Returns:
        `this`
      See Also:
        getProjectDir()

    - #### public GradleRunner withTestKitDir(File testKitDir)

      Sets the directory to use for TestKit's working storage needs.

      This directory is used internally to store various files required by the runner. If no explicit Gradle user home is specified via the build arguments (i.e. the `-g «dir»` option}), this directory will also be used for the Gradle user home for the test build.

      If no value has been specified when the build is initiated, a directory unique to the current operating system user will be created and used within the JVM's temporary directory as advertised by the `java.io.tmpdir` system property. This directory is not deleted by the runner after the test build.

      You may wish to specify a location that is within your project and regularly cleaned, such as the project's build directory.

      The actual contents of this directory are an internal implementation detail and may change at any time.

      Parameters:
        `testKitDir` - the TestKit directory
      Returns:
        `this`
      Since:
        2.7