Enable --build-cache for all func tests

src/funcTest/kotlin/com/github/jengelman/gradle/plugins/shadow/BasePluginTest.kt

@@ -108,6 +108,10 @@ abstract class BasePluginTest {
 
   fun getDefaultSettingsBuildScript(
     startBlock: String = "",
+    // Use a test-specific build cache directory. This ensures that we'll only use cached outputs generated during
+    // this test, and we won't accidentally use cached outputs from a different test or a different build.
+    // https://docs.gradle.org/current/userguide/build_cache.html#sec:build_cache_configure_local
+    buildCacheBlock: String = "local { directory = file('build-cache') }",
     endBlock: String = "rootProject.name = 'shadow'",
   ): String {
     return """
@@ -118,6 +122,9 @@ abstract class BasePluginTest {
           mavenCentral()
         }
       }
+      buildCache {
+        $buildCacheBlock
+      }
       $endBlock
     """.trimIndent() + System.lineSeparator()
   }
@@ -323,6 +330,7 @@ abstract class BasePluginTest {
     val commonArguments = listOf(
       "--warning-mode=fail",
       "--configuration-cache",
+      "--build-cache",
       "--stacktrace",
     )
 

src/funcTest/kotlin/com/github/jengelman/gradle/plugins/shadow/caching/BaseCachingTest.kt

@@ -5,7 +5,6 @@ import com.github.jengelman.gradle.plugins.shadow.BasePluginTest
 import java.nio.file.NoSuchFileException
 import java.nio.file.Path
 import kotlin.io.path.ExperimentalPathApi
-import kotlin.io.path.appendText
 import kotlin.io.path.copyToRecursively
 import kotlin.io.path.deleteRecursively
 import kotlin.io.path.listDirectoryEntries
@@ -14,29 +13,12 @@ import org.gradle.testkit.runner.TaskOutcome
 import org.gradle.testkit.runner.TaskOutcome.FROM_CACHE
 import org.gradle.testkit.runner.TaskOutcome.SUCCESS
 import org.gradle.testkit.runner.TaskOutcome.UP_TO_DATE
-import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.io.TempDir
 
 abstract class BaseCachingTest : BasePluginTest() {
   @TempDir
   lateinit var alternateDir: Path
 
-  @BeforeEach
-  override fun setup() {
-    super.setup()
-    // Use a test-specific build cache directory. This ensures that we'll only use cached outputs generated during
-    // this test, and we won't accidentally use cached outputs from a different test or a different build.
-    settingsScriptPath.appendText(
-      """
-        buildCache {
-          local {
-            directory = file('build-cache')
-          }
-        }
-      """.trimIndent() + System.lineSeparator(),
-    )
-  }
-
   @OptIn(ExperimentalPathApi::class)
   fun assertShadowJarIsCachedAndRelocatable(
     firstOutcome: TaskOutcome = FROM_CACHE,
@@ -72,7 +54,7 @@ abstract class BaseCachingTest : BasePluginTest() {
     expectedOutcome: TaskOutcome,
     runnerBlock: (GradleRunner) -> GradleRunner = { it },
   ) {
-    val result = run("--build-cache", shadowJarTask, runnerBlock = runnerBlock)
+    val result = run(shadowJarTask, runnerBlock = runnerBlock)
     assertThat(result).taskOutcomeEquals(shadowJarTask, expectedOutcome)
   }
 }