diff --git a/dexpreopt/testing.go b/dexpreopt/testing.go
index 8e90295..4801482 100644
--- a/dexpreopt/testing.go
+++ b/dexpreopt/testing.go
@@ -15,39 +15,78 @@
 package dexpreopt
 
 import (
+	"fmt"
+
 	"android/soong/android"
 )
 
-type dummyToolBinary struct {
+type fakeToolBinary struct {
 	android.ModuleBase
 }
 
-func (m *dummyToolBinary) GenerateAndroidBuildActions(ctx android.ModuleContext) {}
+func (m *fakeToolBinary) GenerateAndroidBuildActions(ctx android.ModuleContext) {}
 
-func (m *dummyToolBinary) HostToolPath() android.OptionalPath {
+func (m *fakeToolBinary) HostToolPath() android.OptionalPath {
 	return android.OptionalPathForPath(android.PathForTesting("dex2oat"))
 }
 
-func dummyToolBinaryFactory() android.Module {
-	module := &dummyToolBinary{}
+func fakeToolBinaryFactory() android.Module {
+	module := &fakeToolBinary{}
 	android.InitAndroidArchModule(module, android.HostSupported, android.MultilibFirst)
 	return module
 }
 
 func RegisterToolModulesForTest(ctx android.RegistrationContext) {
-	ctx.RegisterModuleType("dummy_tool_binary", dummyToolBinaryFactory)
+	ctx.RegisterModuleType("fake_tool_binary", fakeToolBinaryFactory)
 }
 
 func BpToolModulesForTest() string {
 	return `
-		dummy_tool_binary {
+		fake_tool_binary {
 			name: "dex2oatd",
 		}
 	`
 }
 
-// Prepares a test fixture by enabling dexpreopt.
-var PrepareForTestWithDexpreopt = FixtureModifyGlobalConfig(func(*GlobalConfig) {})
+func CompatLibDefinitionsForTest() string {
+	bp := ""
+
+	// For class loader context and <uses-library> tests.
+	dexpreoptModules := []string{"android.test.runner"}
+	dexpreoptModules = append(dexpreoptModules, CompatUsesLibs...)
+	dexpreoptModules = append(dexpreoptModules, OptionalCompatUsesLibs...)
+
+	for _, extra := range dexpreoptModules {
+		bp += fmt.Sprintf(`
+			java_library {
+				name: "%s",
+				srcs: ["a.java"],
+				sdk_version: "none",
+				system_modules: "stable-core-platform-api-stubs-system-modules",
+				compile_dex: true,
+				installable: true,
+			}
+		`, extra)
+	}
+
+	return bp
+}
+
+var PrepareForTestWithDexpreoptCompatLibs = android.GroupFixturePreparers(
+	android.FixtureAddFile("defaults/dexpreopt/compat/a.java", nil),
+	android.FixtureAddTextFile("defaults/dexpreopt/compat/Android.bp", CompatLibDefinitionsForTest()),
+)
+
+var PrepareForTestWithFakeDex2oatd = android.GroupFixturePreparers(
+	android.FixtureRegisterWithContext(RegisterToolModulesForTest),
+	android.FixtureAddTextFile("defaults/dexpreopt/Android.bp", BpToolModulesForTest()),
+)
+
+// Prepares a test fixture by enabling dexpreopt, registering the fake_tool_binary module type and
+// using that to define the `dex2oatd` module.
+var PrepareForTestByEnablingDexpreopt = android.GroupFixturePreparers(
+	FixtureModifyGlobalConfig(func(*GlobalConfig) {}),
+)
 
 // FixtureModifyGlobalConfig enables dexpreopt (unless modified by the mutator) and modifies the
 // configuration.
diff --git a/java/java_test.go b/java/java_test.go
index b6f639f..31eeb6b 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -53,7 +53,7 @@
 	android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 		ctx.RegisterPreSingletonType("sdk_versions", sdkPreSingletonFactory)
 	}),
-	dexpreopt.PrepareForTestWithDexpreopt,
+	PrepareForTestWithDexpreopt,
 )
 
 func TestMain(m *testing.M) {
@@ -68,7 +68,7 @@
 func testJavaError(t *testing.T, pattern string, bp string) (*android.TestContext, android.Config) {
 	t.Helper()
 	result := android.GroupFixturePreparers(
-		prepareForJavaTest, dexpreopt.PrepareForTestWithDexpreopt).
+		prepareForJavaTest, dexpreopt.PrepareForTestByEnablingDexpreopt).
 		ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(pattern)).
 		RunTestWithBp(t, bp)
 	return result.TestContext, result.Config
diff --git a/java/testing.go b/java/testing.go
index 82a2103..295b8d0 100644
--- a/java/testing.go
+++ b/java/testing.go
@@ -43,7 +43,7 @@
 	// Make sure that mutators and module types, e.g. prebuilt mutators available.
 	android.PrepareForTestWithAndroidBuildComponents,
 	// Make java build components available to the test.
-	android.FixtureRegisterWithContext(RegisterRequiredBuildComponentsForTest),
+	android.FixtureRegisterWithContext(registerRequiredBuildComponentsForTest),
 	android.FixtureRegisterWithContext(registerJavaPluginBuildComponents),
 )
 
@@ -52,7 +52,16 @@
 	// Make sure that all the module types used in the defaults are registered.
 	PrepareForTestWithJavaBuildComponents,
 	// The java default module definitions.
-	android.FixtureAddTextFile(defaultJavaDir+"/Android.bp", GatherRequiredDepsForTest()),
+	android.FixtureAddTextFile(defaultJavaDir+"/Android.bp", gatherRequiredDepsForTest()),
+	// Add dexpreopt compat libs (android.test.base, etc.) and a fake dex2oatd module.
+	dexpreopt.PrepareForTestWithDexpreoptCompatLibs,
+	dexpreopt.PrepareForTestWithFakeDex2oatd,
+)
+
+// Provides everything needed by dexpreopt.
+var PrepareForTestWithDexpreopt = android.GroupFixturePreparers(
+	PrepareForTestWithJavaDefaultModules,
+	dexpreopt.PrepareForTestByEnablingDexpreopt,
 )
 
 var PrepareForTestWithOverlayBuildComponents = android.FixtureRegisterWithContext(registerOverlayBuildComponents)
@@ -178,7 +187,22 @@
 //
 // In particular this must register all the components that are used in the `Android.bp` snippet
 // returned by GatherRequiredDepsForTest()
+//
+// deprecated: Use test fixtures instead, e.g. PrepareForTestWithJavaBuildComponents
 func RegisterRequiredBuildComponentsForTest(ctx android.RegistrationContext) {
+	registerRequiredBuildComponentsForTest(ctx)
+
+	// Make sure that any tool related module types needed by dexpreopt have been registered.
+	dexpreopt.RegisterToolModulesForTest(ctx)
+}
+
+// registerRequiredBuildComponentsForTest registers the build components used by
+// PrepareForTestWithJavaDefaultModules.
+//
+// As functionality is moved out of here into separate FixturePreparer instances they should also
+// be moved into GatherRequiredDepsForTest for use by tests that have not yet switched to use test
+// fixtures.
+func registerRequiredBuildComponentsForTest(ctx android.RegistrationContext) {
 	RegisterAARBuildComponents(ctx)
 	RegisterAppBuildComponents(ctx)
 	RegisterAppImportBuildComponents(ctx)
@@ -193,15 +217,32 @@
 	RegisterSdkLibraryBuildComponents(ctx)
 	RegisterStubsBuildComponents(ctx)
 	RegisterSystemModulesBuildComponents(ctx)
-
-	// Make sure that any tool related module types needed by dexpreopt have been registered.
-	dexpreopt.RegisterToolModulesForTest(ctx)
 }
 
 // Gather the module definitions needed by tests that depend upon code from this package.
 //
 // Returns an `Android.bp` snippet that defines the modules that are needed by this package.
+//
+// deprecated: Use test fixtures instead, e.g. PrepareForTestWithJavaDefaultModules
 func GatherRequiredDepsForTest() string {
+	bp := gatherRequiredDepsForTest()
+
+	// For class loader context and <uses-library> tests.
+	bp += dexpreopt.CompatLibDefinitionsForTest()
+
+	// Make sure that any tools needed for dexpreopting are defined.
+	bp += dexpreopt.BpToolModulesForTest()
+
+	return bp
+}
+
+// gatherRequiredDepsForTest gathers the module definitions used by
+// PrepareForTestWithJavaDefaultModules.
+//
+// As functionality is moved out of here into separate FixturePreparer instances they should also
+// be moved into GatherRequiredDepsForTest for use by tests that have not yet switched to use test
+// fixtures.
+func gatherRequiredDepsForTest() string {
 	var bp string
 
 	extraModules := []string{
@@ -233,24 +274,6 @@
 		`, extra)
 	}
 
-	// For class loader context and <uses-library> tests.
-	dexpreoptModules := []string{"android.test.runner"}
-	dexpreoptModules = append(dexpreoptModules, dexpreopt.CompatUsesLibs...)
-	dexpreoptModules = append(dexpreoptModules, dexpreopt.OptionalCompatUsesLibs...)
-
-	for _, extra := range dexpreoptModules {
-		bp += fmt.Sprintf(`
-			java_library {
-				name: "%s",
-				srcs: ["a.java"],
-				sdk_version: "none",
-				system_modules: "stable-core-platform-api-stubs-system-modules",
-				compile_dex: true,
-				installable: true,
-			}
-		`, extra)
-	}
-
 	bp += `
 		java_library {
 			name: "framework",
@@ -287,9 +310,6 @@
 		`, extra)
 	}
 
-	// Make sure that any tools needed for dexpreopting are defined.
-	bp += dexpreopt.BpToolModulesForTest()
-
 	// Make sure that the dex_bootjars singleton module is instantiated for the tests.
 	bp += `
 		dex_bootjars {