Rename the internal versions of OutputCapture to prevent accidental
import.

See gh-5492

Replace the internal EnvironmentTestUtils using in `spring-boot` tests
with Spring's TestPropertySourceUtils.

Fixes gh-5492

* pr/5458:
  Polish contribution
  Add Neo4j support

This commit polihes the original Neo4j contribution in several areas.

Rather than providing the packages to scan, this commit rearranges the
`EntityScan` and `EntityScanRegistrar` so that the logic can be shared
for other components. If no package is provided, scanning now defaults to
the "auto-configured" package(s) and a `@NodeEntityScan` annotation
allows to override that.

The configuration has also been updated to detect the driver based on the
`uri` property. If the embedded driver is available we use that by
default. If it is not available, we're trying to connect to a Neo4j
server running on localhost. It is possible to disable the embedded mode
or set the `uri` parameter explicitly to deviate from these defaults.

The sample no longer relies on the embedded driver for licensing reason:
rather it expects an instance running on localhost (like other
data-related samples) and gracefully ignore any connection error. A
README has been added in the sample to further explain the available
options;

Closes gh-5458

See gh-5458

* pr/5489:
  Upgrade Spring AMQP to 1.5.5.RELEASE

Closes gh-5489

Closes gh-5264

Closes gh-5422

Closes gh-5486

Closes gh-5261

Previously, when defining a package for a class, LaunchedURLClassLoader
would use the manifest from the first location that contained the
required package. If the package was split across multiple locations,
this could lead to the manifest from a jar other than the one that
contains the class being used.

This commit updates LaunchedURLClassLoader so that it will use the
manifest of the jar file that contains the class which triggered the
definition of the package.

Closes gh-5485

LaunchedURLClassLoader preemptively defines the package for any
classes that it attempts to load so that the manifest from a nested
jar is correctly associated with the package. This can lead to a race
where the package is defined on two threads in parallel, resulting
in an IllegalArgumentException being thrown.

This problem was manifesting itself as a NoClassDefFoundError.
If the initialization of a class failed due to the above-described
IllegalArgumentException, subsequent attempts to use that class
would then fail with a NoClassDefFoundError.

This commit updates LaunchedURLClassLoader to catch the
IllegalArgumentException and then double-check that the package has
already been defined. This approach, including thrown an
AssertionError when the second check fails, is modelled on the
approach taken by URLClassLoader.

Closes gh-5464

This commit documents the new `InfoContributor` infrastructure.

Closes gh-2559

The commit adds a new BuildInfo task that can be used to generate
a build.properties file, intended for inclusion in the Actuator's
info endpoint.

A default instance of the task can be configure using the plugin's
DSL:

springBoot {
	buildInfo()
}

Additional properties can also be configured using the DSL:

springBoot {
	buildInfo {
		additionalProperties = [
			'foo': 'bar'
		]
	}
}

When configured via the DSL, the Java plugin's classes task is
configured to depend on the build info task. Alternatively, if more
control is required, the task can be declared and configured manually:

task buildInfo(type: org.springframework.boot.gradle.buildinfo.BuildInfo) {
	additionalProperties = [
		'foo': 'bar'
	]
}

classes {
	dependsOn buildInfo
}

See gh-2559

Closes gh-4901

Add a sample application that demonstrates recently added testing
features.

See gh-4901

Add @DataJpaTest and @AutoConfigureTestDatabase annotations to allow
testing of an application "slice" that only deals JPA.

See gh-4901

Add @WebMvcTest and @AutoConfigureMockMvc annotations to allow testing
of an application "slice" that only deals with Spring MVC.

See gh-4901

Add @JsonTest and @AutoConfigureJsonTesters annotations to allow testing
of an application "slice" that only deals with JSON marshalling.

See gh-4901

Provide a way for auto-configuration tests to easily filter scanned
components.

See gh-4901

Add @PropertyMapping annotation which can be used to mark annotation
attributes that should contribute Environment properties.

Provides a quick way for tests to change auto-configuration behavior in
a structured way.

Fixes gh-4901

Add a TestExecutionListener to print the auto-configuration report
when a test cannot load.

See gh-4901

Add a new test module to deal with auto-configuration in tests.

See gh-4901

Provide a way for full auto-configuration to be disabled
programmatically. Primarily added to allow special test annotations to
take over partial auto-configuration but still load
@SpringBootApplication classes.

See gh-4901

Update `@ImportAutoConfiguration` so that it can be used as a
meta-annotation. Also relocate it from the `test` package.

Fixes gh-5473

Remove the need for a nested @Configuration class when writing a test
that need to @Import configuration.

Primarily added to allow @ImportAutoConfiguration to be used directly
on test classes.

Fixes gh-5473

Add a ContextCustomizerFactory to provide TestRestTemplate as a bean for
tests annotated with WebIntegrationTests. Additionally provide support
for automatically expanding URLs of the form `/example` to
`http://localhost:${local.server.port}/example`.

Fixes gh-5227

Provide variants of `WebClient` and `WebConnectionHtmlUnitDriver` that
automatically resolve relative URLs to "localhost:${local.server.port}".

Fixes gh-5472

Add Jackson, Gson and Basic String helper classes that allow AssertJ
assertions to be used to test JSON.

Fixes gh-5471