sdk/testing.go - LeafOS-Project/android_build_soong - Gitiles

 // Copyright 2019 Google Inc. All rights reserved.
 //
 // 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 sdk

 import (
 	"fmt"
 	"path/filepath"
 	"strings"
 	"testing"

 	"android/soong/android"
 	"android/soong/apex"
 	"android/soong/cc"
 	"android/soong/genrule"
 	"android/soong/java"

 	"github.com/google/blueprint/proptools"
 )

 // Prepare for running an sdk test with an apex.
 var prepareForSdkTestWithApex = android.GroupFixturePreparers(
 	apex.PrepareForTestWithApexBuildComponents,
 	android.FixtureAddTextFile("sdk/tests/Android.bp", `
 		apex_key {
 			name: "myapex.key",
 			public_key: "myapex.avbpubkey",
 			private_key: "myapex.pem",
 		}

 		android_app_certificate {
 			name: "myapex.cert",
 			certificate: "myapex",
 		}
 	`),

 	android.FixtureMergeMockFs(map[string][]byte{
 		"apex_manifest.json":                           nil,
 		"system/sepolicy/apex/myapex-file_contexts":    nil,
 		"system/sepolicy/apex/myapex2-file_contexts":   nil,
 		"system/sepolicy/apex/mysdkapex-file_contexts": nil,
 		"sdk/tests/myapex.avbpubkey":                   nil,
 		"sdk/tests/myapex.pem":                         nil,
 		"sdk/tests/myapex.x509.pem":                    nil,
 		"sdk/tests/myapex.pk8":                         nil,
 	}),
 )

 // Legacy preparer used for running tests within the sdk package.
 //
 // This includes everything that was needed to run any test in the sdk package prior to the
 // introduction of the test fixtures. Tests that are being converted to use fixtures directly
 // rather than through the testSdkError() and testSdkWithFs() methods should avoid using this and
 // instead should use the various preparers directly using android.GroupFixturePreparers(...) to
 // group them when necessary.
 //
 // deprecated
 var prepareForSdkTest = android.GroupFixturePreparers(
 	cc.PrepareForTestWithCcDefaultModules,
 	genrule.PrepareForTestWithGenRuleBuildComponents,
 	java.PrepareForTestWithJavaBuildComponents,
 	PrepareForTestWithSdkBuildComponents,

 	prepareForSdkTestWithApex,

 	cc.PrepareForTestOnWindows,
 	android.FixtureModifyConfig(func(config android.Config) {
 		// Add windows as a default disable OS to test behavior when some OS variants
 		// are disabled.
 		config.Targets[android.Windows] = []android.Target{
 			{android.Windows, android.Arch{ArchType: android.X86_64}, android.NativeBridgeDisabled, "", "", true},
 		}
 	}),

 	// Add a build number file.
 	android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 		variables.BuildNumberFile = proptools.StringPtr(BUILD_NUMBER_FILE)
 	}),

 	// Make sure that every test provides all the source files.
 	android.PrepareForTestDisallowNonExistentPaths,
 	android.MockFS{
 		"Test.java": nil,
 	}.AddToFixture(),
 )

 var PrepareForTestWithSdkBuildComponents = android.GroupFixturePreparers(
 	android.FixtureRegisterWithContext(registerModuleExportsBuildComponents),
 	android.FixtureRegisterWithContext(registerSdkBuildComponents),
 )

 func testSdkWithFs(t *testing.T, bp string, fs android.MockFS) *android.TestResult {
 	t.Helper()
 	return android.GroupFixturePreparers(
 		prepareForSdkTest,
 		fs.AddToFixture(),
 	).RunTestWithBp(t, bp)
 }

 func testSdkError(t *testing.T, pattern, bp string) {
 	t.Helper()
 	prepareForSdkTest.
 		ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(pattern)).
 		RunTestWithBp(t, bp)
 }

 func ensureListContains(t *testing.T, result []string, expected string) {
 	t.Helper()
 	if !android.InList(expected, result) {
 		t.Errorf("%q is not found in %v", expected, result)
 	}
 }

 // Analyse the sdk build rules to extract information about what it is doing.
 //
 // e.g. find the src/dest pairs from each cp command, the various zip files
 // generated, etc.
 func getSdkSnapshotBuildInfo(t *testing.T, result *android.TestResult, sdk *sdk) *snapshotBuildInfo {
 	info := &snapshotBuildInfo{
 		t:                          t,
 		r:                          result,
 		androidBpContents:          sdk.GetAndroidBpContentsForTests(),
 		infoContents:               sdk.GetInfoContentsForTests(),
 		snapshotTestCustomizations: map[snapshotTest]*snapshotTestCustomization{},
 		targetBuildRelease:         sdk.builderForTests.targetBuildRelease,
 	}

 	buildParams := sdk.BuildParamsForTests()
 	copyRules := &strings.Builder{}
 	otherCopyRules := &strings.Builder{}
 	snapshotDirPrefix := sdk.builderForTests.snapshotDir.String() + "/"

 	seenBuildNumberFile := false
 	for _, bp := range buildParams {
 		switch bp.Rule.String() {
 		case android.Cp.String():
 			output := bp.Output
 			// Get destination relative to the snapshot root
 			dest := output.Rel()
 			src := android.NormalizePathForTesting(bp.Input)
 			// We differentiate between copy rules for the snapshot, and copy rules for the install file.
 			if strings.HasPrefix(output.String(), snapshotDirPrefix) {
 				// Don't include the build-number.txt file in the copy rules as that would break lots of
 				// tests, just verify that it is copied here as it should appear in every snapshot.
 				if output.Base() == BUILD_NUMBER_FILE {
 					seenBuildNumberFile = true
 				} else {
 					// Get source relative to build directory.
 					_, _ = fmt.Fprintf(copyRules, "%s -> %s\n", src, dest)
 				}
 				info.snapshotContents = append(info.snapshotContents, dest)
 			} else {
 				_, _ = fmt.Fprintf(otherCopyRules, "%s -> %s\n", src, dest)
 			}

 		case repackageZip.String():
 			// Add the destdir to the snapshot contents as that is effectively where
 			// the content of the repackaged zip is copied.
 			dest := bp.Args["destdir"]
 			info.snapshotContents = append(info.snapshotContents, dest)

 		case zipFiles.String():
 			// This could be an intermediate zip file and not the actual output zip.
 			// In that case this will be overridden when the rule to merge the zips
 			// is processed.
 			info.outputZip = android.NormalizePathForTesting(bp.Output)

 		case mergeZips.String():
 			// Copy the current outputZip to the intermediateZip.
 			info.intermediateZip = info.outputZip
 			mergeInput := android.NormalizePathForTesting(bp.Input)
 			if info.intermediateZip != mergeInput {
 				t.Errorf("Expected intermediate zip %s to be an input to merge zips but found %s instead",
 					info.intermediateZip, mergeInput)
 			}

 			// Override output zip (which was actually the intermediate zip file) with the actual
 			// output zip.
 			info.outputZip = android.NormalizePathForTesting(bp.Output)

 			// Save the zips to be merged into the intermediate zip.
 			info.mergeZips = android.NormalizePathsForTesting(bp.Inputs)
 		}
 	}

 	if !seenBuildNumberFile {
 		panic(fmt.Sprintf("Every snapshot must include the %s file", BUILD_NUMBER_FILE))
 	}

 	info.copyRules = copyRules.String()
 	info.otherCopyRules = otherCopyRules.String()

 	return info
 }

 // The enum of different sdk snapshot tests performed by CheckSnapshot.
 type snapshotTest int

 const (
 	// The enumeration of the different test configurations.
 	// A test with the snapshot/Android.bp file but without the original Android.bp file.
 	checkSnapshotWithoutSource snapshotTest = iota

 	// A test with both the original source and the snapshot, with the source preferred.
 	checkSnapshotWithSourcePreferred

 	// A test with both the original source and the snapshot, with the snapshot preferred.
 	checkSnapshotPreferredWithSource

 	// The directory into which the snapshot will be 'unpacked'.
 	snapshotSubDir = "snapshot"
 )

 // Check the snapshot build rules.
 //
 // Takes a list of functions which check different facets of the snapshot build rules.
 // Allows each test to customize what is checked without duplicating lots of code
 // or proliferating check methods of different flavors.
 func CheckSnapshot(t *testing.T, result *android.TestResult, name string, dir string, checkers ...snapshotBuildInfoChecker) {
 	t.Helper()

 	// The sdk CommonOS variant is always responsible for generating the snapshot.
 	variant := android.CommonOS.Name

 	sdk := result.Module(name, variant).(*sdk)

 	snapshotBuildInfo := getSdkSnapshotBuildInfo(t, result, sdk)

 	// Check state of the snapshot build.
 	for _, checker := range checkers {
 		checker(snapshotBuildInfo)
 	}

 	// Make sure that the generated zip file is in the correct place.
 	actual := snapshotBuildInfo.outputZip
 	if dir != "" {
 		dir = filepath.Clean(dir) + "/"
 	}
 	suffix := "-" + soongSdkSnapshotVersionCurrent

 	expectedZipPath := fmt.Sprintf(".intermediates/%s%s/%s/%s%s.zip", dir, name, variant, name, suffix)
 	android.AssertStringEquals(t, "Snapshot zip file in wrong place", expectedZipPath, actual)

 	// Populate a mock filesystem with the files that would have been copied by
 	// the rules.
 	fs := android.MockFS{}
 	for _, dest := range snapshotBuildInfo.snapshotContents {
 		fs[filepath.Join(snapshotSubDir, dest)] = nil
 	}
 	fs[filepath.Join(snapshotSubDir, "Android.bp")] = []byte(snapshotBuildInfo.androidBpContents)

 	// If the generated snapshot builders not for the current release then it cannot be loaded by
 	// the current release.
 	currentBuildRelease := latestBuildRelease()
 	if snapshotBuildInfo.targetBuildRelease != currentBuildRelease {
 		return
 	}

 	// The preparers from the original source fixture.
 	sourcePreparers := result.Preparer()

 	// Preparer to combine the snapshot and the source.
 	snapshotPreparer := android.GroupFixturePreparers(sourcePreparers, fs.AddToFixture())

 	var runSnapshotTestWithCheckers = func(t *testing.T, testConfig snapshotTest, extraPreparer android.FixturePreparer) {
 		t.Helper()
 		customization := snapshotBuildInfo.snapshotTestCustomization(testConfig)
 		customizedPreparers := android.GroupFixturePreparers(customization.preparers...)

 		// TODO(b/183184375): Set Config.TestAllowNonExistentPaths = false to verify that all the
 		//  files the snapshot needs are actually copied into the snapshot.

 		// Run the snapshot with the snapshot preparer and the extra preparer, which must come after as
 		// it may need to modify parts of the MockFS populated by the snapshot preparer.
 		result := android.GroupFixturePreparers(snapshotPreparer, extraPreparer, customizedPreparers).
 			ExtendWithErrorHandler(customization.errorHandler).
 			RunTest(t)

 		// Perform any additional checks the test need on the result of processing the snapshot.
 		for _, checker := range customization.checkers {
 			checker(t, result)
 		}
 	}

 	t.Run("snapshot without source", func(t *testing.T) {
 		// Remove the source Android.bp file to make sure it works without.
 		removeSourceAndroidBp := android.FixtureModifyMockFS(func(fs android.MockFS) {
 			delete(fs, "Android.bp")
 		})

 		runSnapshotTestWithCheckers(t, checkSnapshotWithoutSource, removeSourceAndroidBp)
 	})

 	t.Run("snapshot with source preferred", func(t *testing.T) {
 		runSnapshotTestWithCheckers(t, checkSnapshotWithSourcePreferred, android.NullFixturePreparer)
 	})

 	t.Run("snapshot preferred with source", func(t *testing.T) {
 		// Replace the snapshot/Android.bp file with one where "prefer: false," has been replaced with
 		// "prefer: true,"
 		preferPrebuilts := android.FixtureModifyMockFS(func(fs android.MockFS) {
 			snapshotBpFile := filepath.Join(snapshotSubDir, "Android.bp")
 			unpreferred := string(fs[snapshotBpFile])
 			fs[snapshotBpFile] = []byte(strings.ReplaceAll(unpreferred, "prefer: false,", "prefer: true,"))
 		})

 		runSnapshotTestWithCheckers(t, checkSnapshotPreferredWithSource, preferPrebuilts)
 	})
 }

 type snapshotBuildInfoChecker func(info *snapshotBuildInfo)

 // Check that the snapshot's generated Android.bp is correct.
 //
 // Both the expected and actual string are both trimmed before comparing.
 func checkAndroidBpContents(expected string) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		info.t.Helper()
 		android.AssertTrimmedStringEquals(info.t, "Android.bp contents do not match", expected, info.androidBpContents)
 	}
 }

 // Check that the snapshot's copy rules are correct.
 //
 // The copy rules are formatted as <src> -> <dest>, one per line and then compared
 // to the supplied expected string. Both the expected and actual string are trimmed
 // before comparing.
 func checkAllCopyRules(expected string) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		info.t.Helper()
 		android.AssertTrimmedStringEquals(info.t, "Incorrect copy rules", expected, info.copyRules)
 	}
 }

 func checkAllOtherCopyRules(expected string) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		info.t.Helper()
 		android.AssertTrimmedStringEquals(info.t, "Incorrect copy rules", expected, info.otherCopyRules)
 	}
 }

 // Check that the specified paths match the list of zips to merge with the intermediate zip.
 func checkMergeZips(expected ...string) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		info.t.Helper()
 		if info.intermediateZip == "" {
 			info.t.Errorf("No intermediate zip file was created")
 		}

 		android.AssertDeepEquals(info.t, "mismatching merge zip files", expected, info.mergeZips)
 	}
 }

 // Check that the snapshot's info contents are ciorrect.
 //
 // Both the expected and actual string are both trimmed before comparing.
 func checkInfoContents(config android.Config, expected string) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		info.t.Helper()
 		android.AssertTrimmedStringEquals(info.t, "info contents do not match",
 			expected, android.StringRelativeToTop(config, info.infoContents))
 	}
 }

 type resultChecker func(t *testing.T, result *android.TestResult)

 // snapshotTestPreparer registers a preparer that will be used to customize the specified
 // snapshotTest.
 func snapshotTestPreparer(snapshotTest snapshotTest, preparer android.FixturePreparer) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		customization := info.snapshotTestCustomization(snapshotTest)
 		customization.preparers = append(customization.preparers, preparer)
 	}
 }

 // snapshotTestChecker registers a checker that will be run against the result of processing the
 // generated snapshot for the specified snapshotTest.
 func snapshotTestChecker(snapshotTest snapshotTest, checker resultChecker) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		customization := info.snapshotTestCustomization(snapshotTest)
 		customization.checkers = append(customization.checkers, checker)
 	}
 }

 // snapshotTestErrorHandler registers an error handler to use when processing the snapshot
 // in the specific test case.
 //
 // Generally, the snapshot should work with all the test cases but some do not and just in case
 // there are a lot of issues to resolve, or it will take a lot of time this is a
 // get-out-of-jail-free card that allows progress to be made.
 //
 // deprecated: should only be used as a temporary workaround with an attached to do and bug.
 func snapshotTestErrorHandler(snapshotTest snapshotTest, handler android.FixtureErrorHandler) snapshotBuildInfoChecker {
 	return func(info *snapshotBuildInfo) {
 		customization := info.snapshotTestCustomization(snapshotTest)
 		customization.errorHandler = handler
 	}
 }

 // Encapsulates information provided by each test to customize a specific snapshotTest.
 type snapshotTestCustomization struct {
 	// Preparers that are used to customize the test fixture before running the test.
 	preparers []android.FixturePreparer

 	// Checkers that are run on the result of processing the preferred snapshot in a specific test
 	// case.
 	checkers []resultChecker

 	// Specify an error handler for when processing a specific test case.
 	//
 	// In some cases the generated snapshot cannot be used in a test configuration. Those cases are
 	// invariably bugs that need to be resolved but sometimes that can take a while. This provides a
 	// mechanism to temporarily ignore that error.
 	errorHandler android.FixtureErrorHandler
 }

 // Encapsulates information about the snapshot build structure in order to insulate tests from
 // knowing too much about internal structures.
 //
 // All source/input paths are relative either the build directory. All dest/output paths are
 // relative to the snapshot root directory.
 type snapshotBuildInfo struct {
 	t *testing.T

 	// The result from RunTest()
 	r *android.TestResult

 	// The contents of the generated Android.bp file
 	androidBpContents string

 	// The contents of the info file.
 	infoContents string

 	// The paths, relative to the snapshot root, of all files and directories copied into the
 	// snapshot.
 	snapshotContents []string

 	// A formatted representation of the src/dest pairs for a snapshot, one pair per line,
 	// of the format src -> dest
 	copyRules string

 	// A formatted representation of the src/dest pairs for files not in a snapshot, one pair
 	// per line, of the format src -> dest
 	otherCopyRules string

 	// The path to the intermediate zip, which is a zip created from the source files copied
 	// into the snapshot directory and which will be merged with other zips to form the final output.
 	// Is am empty string if there is no intermediate zip because there are no zips to merge in.
 	intermediateZip string

 	// The paths to the zips to merge into the output zip, does not include the intermediate
 	// zip.
 	mergeZips []string

 	// The final output zip.
 	outputZip string

 	// The target build release.
 	targetBuildRelease *buildRelease

 	// The test specific customizations for each snapshot test.
 	snapshotTestCustomizations map[snapshotTest]*snapshotTestCustomization
 }

 // snapshotTestCustomization gets the test specific customization for the specified snapshotTest.
 //
 // If no customization was created previously then it creates a default customization.
 func (i *snapshotBuildInfo) snapshotTestCustomization(snapshotTest snapshotTest) *snapshotTestCustomization {
 	customization := i.snapshotTestCustomizations[snapshotTest]
 	if customization == nil {
 		customization = &snapshotTestCustomization{
 			errorHandler: android.FixtureExpectsNoErrors,
 		}
 		i.snapshotTestCustomizations[snapshotTest] = customization
 	}
 	return customization
 }
	// Copyright 2019 Google Inc. All rights reserved.
	//
	// 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 sdk

	import (
	"fmt"
	"path/filepath"
	"strings"
	"testing"

	"android/soong/android"
	"android/soong/apex"
	"android/soong/cc"
	"android/soong/genrule"
	"android/soong/java"

	"github.com/google/blueprint/proptools"
	)

	// Prepare for running an sdk test with an apex.
	var prepareForSdkTestWithApex = android.GroupFixturePreparers(
	apex.PrepareForTestWithApexBuildComponents,
	android.FixtureAddTextFile("sdk/tests/Android.bp", `
	apex_key {
	name: "myapex.key",
	public_key: "myapex.avbpubkey",
	private_key: "myapex.pem",
	}

	android_app_certificate {
	name: "myapex.cert",
	certificate: "myapex",
	}
	`),

	android.FixtureMergeMockFs(map[string][]byte{
	"apex_manifest.json": nil,
	"system/sepolicy/apex/myapex-file_contexts": nil,
	"system/sepolicy/apex/myapex2-file_contexts": nil,
	"system/sepolicy/apex/mysdkapex-file_contexts": nil,
	"sdk/tests/myapex.avbpubkey": nil,
	"sdk/tests/myapex.pem": nil,
	"sdk/tests/myapex.x509.pem": nil,
	"sdk/tests/myapex.pk8": nil,
	}),
	)

	// Legacy preparer used for running tests within the sdk package.
	//
	// This includes everything that was needed to run any test in the sdk package prior to the
	// introduction of the test fixtures. Tests that are being converted to use fixtures directly
	// rather than through the testSdkError() and testSdkWithFs() methods should avoid using this and
	// instead should use the various preparers directly using android.GroupFixturePreparers(...) to
	// group them when necessary.
	//
	// deprecated
	var prepareForSdkTest = android.GroupFixturePreparers(
	cc.PrepareForTestWithCcDefaultModules,
	genrule.PrepareForTestWithGenRuleBuildComponents,
	java.PrepareForTestWithJavaBuildComponents,
	PrepareForTestWithSdkBuildComponents,

	prepareForSdkTestWithApex,

	cc.PrepareForTestOnWindows,
	android.FixtureModifyConfig(func(config android.Config) {
	// Add windows as a default disable OS to test behavior when some OS variants
	// are disabled.
	config.Targets[android.Windows] = []android.Target{
	{android.Windows, android.Arch{ArchType: android.X86_64}, android.NativeBridgeDisabled, "", "", true},
	}
	}),

	// Add a build number file.
	android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
	variables.BuildNumberFile = proptools.StringPtr(BUILD_NUMBER_FILE)
	}),

	// Make sure that every test provides all the source files.
	android.PrepareForTestDisallowNonExistentPaths,
	android.MockFS{
	"Test.java": nil,
	}.AddToFixture(),
	)

	var PrepareForTestWithSdkBuildComponents = android.GroupFixturePreparers(
	android.FixtureRegisterWithContext(registerModuleExportsBuildComponents),
	android.FixtureRegisterWithContext(registerSdkBuildComponents),
	)

	func testSdkWithFs(t testing.T, bp string, fs android.MockFS) android.TestResult {
	t.Helper()
	return android.GroupFixturePreparers(
	prepareForSdkTest,
	fs.AddToFixture(),
	).RunTestWithBp(t, bp)
	}

	func testSdkError(t *testing.T, pattern, bp string) {
	t.Helper()
	prepareForSdkTest.
	ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(pattern)).
	RunTestWithBp(t, bp)
	}

	func ensureListContains(t *testing.T, result []string, expected string) {
	t.Helper()
	if !android.InList(expected, result) {
	t.Errorf("%q is not found in %v", expected, result)
	}
	}

	// Analyse the sdk build rules to extract information about what it is doing.
	//
	// e.g. find the src/dest pairs from each cp command, the various zip files
	// generated, etc.
	func getSdkSnapshotBuildInfo(t testing.T, result android.TestResult, sdk sdk) snapshotBuildInfo {
	info := &snapshotBuildInfo{
	t: t,
	r: result,
	androidBpContents: sdk.GetAndroidBpContentsForTests(),
	infoContents: sdk.GetInfoContentsForTests(),
	snapshotTestCustomizations: map[snapshotTest]*snapshotTestCustomization{},
	targetBuildRelease: sdk.builderForTests.targetBuildRelease,
	}

	buildParams := sdk.BuildParamsForTests()
	copyRules := &strings.Builder{}
	otherCopyRules := &strings.Builder{}
	snapshotDirPrefix := sdk.builderForTests.snapshotDir.String() + "/"

	seenBuildNumberFile := false
	for _, bp := range buildParams {
	switch bp.Rule.String() {
	case android.Cp.String():
	output := bp.Output
	// Get destination relative to the snapshot root
	dest := output.Rel()
	src := android.NormalizePathForTesting(bp.Input)
	// We differentiate between copy rules for the snapshot, and copy rules for the install file.
	if strings.HasPrefix(output.String(), snapshotDirPrefix) {
	// Don't include the build-number.txt file in the copy rules as that would break lots of
	// tests, just verify that it is copied here as it should appear in every snapshot.
	if output.Base() == BUILD_NUMBER_FILE {
	seenBuildNumberFile = true
	} else {
	// Get source relative to build directory.
	_, _ = fmt.Fprintf(copyRules, "%s -> %s\n", src, dest)
	}
	info.snapshotContents = append(info.snapshotContents, dest)
	} else {
	_, _ = fmt.Fprintf(otherCopyRules, "%s -> %s\n", src, dest)
	}

	case repackageZip.String():
	// Add the destdir to the snapshot contents as that is effectively where
	// the content of the repackaged zip is copied.
	dest := bp.Args["destdir"]
	info.snapshotContents = append(info.snapshotContents, dest)

	case zipFiles.String():
	// This could be an intermediate zip file and not the actual output zip.
	// In that case this will be overridden when the rule to merge the zips
	// is processed.
	info.outputZip = android.NormalizePathForTesting(bp.Output)

	case mergeZips.String():
	// Copy the current outputZip to the intermediateZip.
	info.intermediateZip = info.outputZip
	mergeInput := android.NormalizePathForTesting(bp.Input)
	if info.intermediateZip != mergeInput {
	t.Errorf("Expected intermediate zip %s to be an input to merge zips but found %s instead",
	info.intermediateZip, mergeInput)
	}

	// Override output zip (which was actually the intermediate zip file) with the actual
	// output zip.
	info.outputZip = android.NormalizePathForTesting(bp.Output)

	// Save the zips to be merged into the intermediate zip.
	info.mergeZips = android.NormalizePathsForTesting(bp.Inputs)
	}
	}

	if !seenBuildNumberFile {
	panic(fmt.Sprintf("Every snapshot must include the %s file", BUILD_NUMBER_FILE))
	}

	info.copyRules = copyRules.String()
	info.otherCopyRules = otherCopyRules.String()

	return info
	}

	// The enum of different sdk snapshot tests performed by CheckSnapshot.
	type snapshotTest int

	const (
	// The enumeration of the different test configurations.
	// A test with the snapshot/Android.bp file but without the original Android.bp file.
	checkSnapshotWithoutSource snapshotTest = iota

	// A test with both the original source and the snapshot, with the source preferred.
	checkSnapshotWithSourcePreferred

	// A test with both the original source and the snapshot, with the snapshot preferred.
	checkSnapshotPreferredWithSource

	// The directory into which the snapshot will be 'unpacked'.
	snapshotSubDir = "snapshot"
	)

	// Check the snapshot build rules.
	//
	// Takes a list of functions which check different facets of the snapshot build rules.
	// Allows each test to customize what is checked without duplicating lots of code
	// or proliferating check methods of different flavors.
	func CheckSnapshot(t testing.T, result android.TestResult, name string, dir string, checkers ...snapshotBuildInfoChecker) {
	t.Helper()

	// The sdk CommonOS variant is always responsible for generating the snapshot.
	variant := android.CommonOS.Name

	sdk := result.Module(name, variant).(*sdk)

	snapshotBuildInfo := getSdkSnapshotBuildInfo(t, result, sdk)

	// Check state of the snapshot build.
	for _, checker := range checkers {
	checker(snapshotBuildInfo)
	}

	// Make sure that the generated zip file is in the correct place.
	actual := snapshotBuildInfo.outputZip
	if dir != "" {
	dir = filepath.Clean(dir) + "/"
	}
	suffix := "-" + soongSdkSnapshotVersionCurrent

	expectedZipPath := fmt.Sprintf(".intermediates/%s%s/%s/%s%s.zip", dir, name, variant, name, suffix)
	android.AssertStringEquals(t, "Snapshot zip file in wrong place", expectedZipPath, actual)

	// Populate a mock filesystem with the files that would have been copied by
	// the rules.
	fs := android.MockFS{}
	for _, dest := range snapshotBuildInfo.snapshotContents {
	fs[filepath.Join(snapshotSubDir, dest)] = nil
	}
	fs[filepath.Join(snapshotSubDir, "Android.bp")] = []byte(snapshotBuildInfo.androidBpContents)

	// If the generated snapshot builders not for the current release then it cannot be loaded by
	// the current release.
	currentBuildRelease := latestBuildRelease()
	if snapshotBuildInfo.targetBuildRelease != currentBuildRelease {
	return
	}

	// The preparers from the original source fixture.
	sourcePreparers := result.Preparer()

	// Preparer to combine the snapshot and the source.
	snapshotPreparer := android.GroupFixturePreparers(sourcePreparers, fs.AddToFixture())

	var runSnapshotTestWithCheckers = func(t *testing.T, testConfig snapshotTest, extraPreparer android.FixturePreparer) {
	t.Helper()
	customization := snapshotBuildInfo.snapshotTestCustomization(testConfig)
	customizedPreparers := android.GroupFixturePreparers(customization.preparers...)

	// TODO(b/183184375): Set Config.TestAllowNonExistentPaths = false to verify that all the
	// files the snapshot needs are actually copied into the snapshot.

	// Run the snapshot with the snapshot preparer and the extra preparer, which must come after as
	// it may need to modify parts of the MockFS populated by the snapshot preparer.
	result := android.GroupFixturePreparers(snapshotPreparer, extraPreparer, customizedPreparers).
	ExtendWithErrorHandler(customization.errorHandler).
	RunTest(t)

	// Perform any additional checks the test need on the result of processing the snapshot.
	for _, checker := range customization.checkers {
	checker(t, result)
	}
	}

	t.Run("snapshot without source", func(t *testing.T) {
	// Remove the source Android.bp file to make sure it works without.
	removeSourceAndroidBp := android.FixtureModifyMockFS(func(fs android.MockFS) {
	delete(fs, "Android.bp")
	})

	runSnapshotTestWithCheckers(t, checkSnapshotWithoutSource, removeSourceAndroidBp)
	})

	t.Run("snapshot with source preferred", func(t *testing.T) {
	runSnapshotTestWithCheckers(t, checkSnapshotWithSourcePreferred, android.NullFixturePreparer)
	})

	t.Run("snapshot preferred with source", func(t *testing.T) {
	// Replace the snapshot/Android.bp file with one where "prefer: false," has been replaced with
	// "prefer: true,"
	preferPrebuilts := android.FixtureModifyMockFS(func(fs android.MockFS) {
	snapshotBpFile := filepath.Join(snapshotSubDir, "Android.bp")
	unpreferred := string(fs[snapshotBpFile])
	fs[snapshotBpFile] = []byte(strings.ReplaceAll(unpreferred, "prefer: false,", "prefer: true,"))
	})

	runSnapshotTestWithCheckers(t, checkSnapshotPreferredWithSource, preferPrebuilts)
	})
	}

	type snapshotBuildInfoChecker func(info *snapshotBuildInfo)

	// Check that the snapshot's generated Android.bp is correct.
	//
	// Both the expected and actual string are both trimmed before comparing.
	func checkAndroidBpContents(expected string) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	info.t.Helper()
	android.AssertTrimmedStringEquals(info.t, "Android.bp contents do not match", expected, info.androidBpContents)
	}
	}

	// Check that the snapshot's copy rules are correct.
	//
	// The copy rules are formatted as <src> -> <dest>, one per line and then compared
	// to the supplied expected string. Both the expected and actual string are trimmed
	// before comparing.
	func checkAllCopyRules(expected string) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	info.t.Helper()
	android.AssertTrimmedStringEquals(info.t, "Incorrect copy rules", expected, info.copyRules)
	}
	}

	func checkAllOtherCopyRules(expected string) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	info.t.Helper()
	android.AssertTrimmedStringEquals(info.t, "Incorrect copy rules", expected, info.otherCopyRules)
	}
	}

	// Check that the specified paths match the list of zips to merge with the intermediate zip.
	func checkMergeZips(expected ...string) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	info.t.Helper()
	if info.intermediateZip == "" {
	info.t.Errorf("No intermediate zip file was created")
	}

	android.AssertDeepEquals(info.t, "mismatching merge zip files", expected, info.mergeZips)
	}
	}

	// Check that the snapshot's info contents are ciorrect.
	//
	// Both the expected and actual string are both trimmed before comparing.
	func checkInfoContents(config android.Config, expected string) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	info.t.Helper()
	android.AssertTrimmedStringEquals(info.t, "info contents do not match",
	expected, android.StringRelativeToTop(config, info.infoContents))
	}
	}

	type resultChecker func(t testing.T, result android.TestResult)

	// snapshotTestPreparer registers a preparer that will be used to customize the specified
	// snapshotTest.
	func snapshotTestPreparer(snapshotTest snapshotTest, preparer android.FixturePreparer) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	customization := info.snapshotTestCustomization(snapshotTest)
	customization.preparers = append(customization.preparers, preparer)
	}
	}

	// snapshotTestChecker registers a checker that will be run against the result of processing the
	// generated snapshot for the specified snapshotTest.
	func snapshotTestChecker(snapshotTest snapshotTest, checker resultChecker) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	customization := info.snapshotTestCustomization(snapshotTest)
	customization.checkers = append(customization.checkers, checker)
	}
	}

	// snapshotTestErrorHandler registers an error handler to use when processing the snapshot
	// in the specific test case.
	//
	// Generally, the snapshot should work with all the test cases but some do not and just in case
	// there are a lot of issues to resolve, or it will take a lot of time this is a
	// get-out-of-jail-free card that allows progress to be made.
	//
	// deprecated: should only be used as a temporary workaround with an attached to do and bug.
	func snapshotTestErrorHandler(snapshotTest snapshotTest, handler android.FixtureErrorHandler) snapshotBuildInfoChecker {
	return func(info *snapshotBuildInfo) {
	customization := info.snapshotTestCustomization(snapshotTest)
	customization.errorHandler = handler
	}
	}

	// Encapsulates information provided by each test to customize a specific snapshotTest.
	type snapshotTestCustomization struct {
	// Preparers that are used to customize the test fixture before running the test.
	preparers []android.FixturePreparer

	// Checkers that are run on the result of processing the preferred snapshot in a specific test
	// case.
	checkers []resultChecker

	// Specify an error handler for when processing a specific test case.
	//
	// In some cases the generated snapshot cannot be used in a test configuration. Those cases are
	// invariably bugs that need to be resolved but sometimes that can take a while. This provides a
	// mechanism to temporarily ignore that error.
	errorHandler android.FixtureErrorHandler
	}

	// Encapsulates information about the snapshot build structure in order to insulate tests from
	// knowing too much about internal structures.
	//
	// All source/input paths are relative either the build directory. All dest/output paths are
	// relative to the snapshot root directory.
	type snapshotBuildInfo struct {
	t *testing.T

	// The result from RunTest()
	r *android.TestResult

	// The contents of the generated Android.bp file
	androidBpContents string

	// The contents of the info file.
	infoContents string

	// The paths, relative to the snapshot root, of all files and directories copied into the
	// snapshot.
	snapshotContents []string

	// A formatted representation of the src/dest pairs for a snapshot, one pair per line,
	// of the format src -> dest
	copyRules string

	// A formatted representation of the src/dest pairs for files not in a snapshot, one pair
	// per line, of the format src -> dest
	otherCopyRules string

	// The path to the intermediate zip, which is a zip created from the source files copied
	// into the snapshot directory and which will be merged with other zips to form the final output.
	// Is am empty string if there is no intermediate zip because there are no zips to merge in.
	intermediateZip string

	// The paths to the zips to merge into the output zip, does not include the intermediate
	// zip.
	mergeZips []string

	// The final output zip.
	outputZip string

	// The target build release.
	targetBuildRelease *buildRelease

	// The test specific customizations for each snapshot test.
	snapshotTestCustomizations map[snapshotTest]*snapshotTestCustomization
	}

	// snapshotTestCustomization gets the test specific customization for the specified snapshotTest.
	//
	// If no customization was created previously then it creates a default customization.
	func (i snapshotBuildInfo) snapshotTestCustomization(snapshotTest snapshotTest) snapshotTestCustomization {
	customization := i.snapshotTestCustomizations[snapshotTest]
	if customization == nil {
	customization = &snapshotTestCustomization{
	errorHandler: android.FixtureExpectsNoErrors,
	}
	i.snapshotTestCustomizations[snapshotTest] = customization
	}
	return customization
	}