Add integration test for module names

integration-tests/src/test/kotlin/com/google/devtools/ksp/test/secondary/InvalidModuleNameIT.kt

diff --git a/integration-tests/src/test/kotlin/com/google/devtools/ksp/test/secondary/InvalidModuleNameIT.kt b/integration-tests/src/test/kotlin/com/google/devtools/ksp/test/secondary/InvalidModuleNameIT.kt
new file mode 100644
index 0000000..a74a15c
--- /dev/null
+++ b/integration-tests/src/test/kotlin/com/google/devtools/ksp/test/secondary/InvalidModuleNameIT.kt
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2026 Google LLC
+ * Copyright 2010-2026 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ *
+ * 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 com.google.devtools.ksp.test.secondary
+
+import com.google.devtools.ksp.test.fixtures.TemporaryTestProject
+import org.gradle.testkit.runner.GradleRunner
+import org.junit.Assert
+import org.junit.Assume
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+import java.io.File
+
+@RunWith(Parameterized::class)
+class InvalidModuleNameIT(experimentalPsiResolution: Boolean) {
+    @Rule
+    @JvmField
+    val project: TemporaryTestProject = TemporaryTestProject(
+        "playground",
+        experimentalPsiResolution = experimentalPsiResolution
+    )
+
+    companion object {
+        @JvmStatic
+        @Parameterized.Parameters
+        fun data(): Collection<Boolean> = listOf(true, false)
+    }
+
+    @Test
+    fun testInvalidModuleName() {
+        // N.B.: The module name is an invalid path name on Windows due to the `:` character.
+        //       However, we only care the KSP logs the sanitized name.
+        Assume.assumeFalse(System.getProperty("os.name").startsWith("Windows", ignoreCase = true))
+        val buildFile = File(project.root, "workload/build.gradle.kts")
+        buildFile.appendText(
+            """
+
+            tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
+                compilerOptions {
+                    moduleName.set("my:invalid:name")
+                }
+            }
+            """.trimIndent()
+        )
+
+        val gradleRunner = GradleRunner.create().withProjectDir(project.root)
+        val result = gradleRunner.withArguments("clean", "build").build()
+
+        Assert.assertTrue(
+            "Expected output to contain log with sanitized module name",
+            result.output.contains($$"[my:invalid:name] Mangled name for internalFun: internalFun$my_invalid_name")
+        )
+        Assert.assertFalse(
+            "Expected output NOT to contain log with UNSANITIZED module name",
+            result.output.contains($$"[my:invalid:name] Mangled name for internalFun: internalFun$my:invalid:name")
+        )
+    }
+}