Fixed error messaging and added tests.

dependency-guard/src/main/kotlin/com/dropbox/gradle/plugins/dependencyguard/internal/DependencyGuardListReportWriter.kt

@@ -38,13 +38,13 @@ internal class DependencyGuardListReportWriter(
             )
             false
         } else {
+            val expectedFileContent = projectDirOutputFile.readText()
             // Perform Diff
             DependencyListDiff.performDiff(
-                type = type,
                 projectPath = report.projectPath,
                 configurationName = report.configurationName,
-                projectDirOutputFile = projectDirOutputFile,
-                depsReportString = reportContent,
+                expectedDependenciesFileContent = expectedFileContent,
+                actualDependenciesFileContent = reportContent,
                 errorHandler = errorHandler
             )
         }

dependency-guard/src/main/kotlin/com/dropbox/gradle/plugins/dependencyguard/internal/utils/DependencyListDiff.kt

@@ -1,8 +1,6 @@
 package com.dropbox.gradle.plugins.dependencyguard.internal.utils
 
-import com.dropbox.gradle.plugins.dependencyguard.DependencyGuardPlugin
-import com.dropbox.gradle.plugins.dependencyguard.internal.DependencyGuardReportType
-import java.io.File
+import com.dropbox.gradle.plugins.dependencyguard.internal.getQualifiedBaselineTaskForProjectPath
 
 internal object DependencyListDiff {
 
@@ -11,23 +9,22 @@ internal object DependencyListDiff {
      */
     @Suppress("LongParameterList")
     fun performDiff(
-        type: DependencyGuardReportType,
         projectPath: String,
         configurationName: String,
-        projectDirOutputFile: File,
-        depsReportString: String,
+        expectedDependenciesFileContent:String,
+        actualDependenciesFileContent: String,
         errorHandler: (String) -> Unit,
     ): Boolean {
         // Compare
-        val expectedFileContent = projectDirOutputFile.readText()
-        val expectedLines = expectedFileContent.lines()
-        val difference = compare(expectedLines, depsReportString.lines())
+        val expectedLines = expectedDependenciesFileContent.lines()
+        val difference = compare(expectedLines, actualDependenciesFileContent.lines())
         if (difference.isNotBlank()) {
+            val dependenciesChangedMessage = """Dependencies Changed in "$projectPath" for configuration "$configurationName""""
             val errorMessage = StringBuilder().apply {
                 appendLine(
                     ColorTerminal.printlnColor(
                         ColorTerminal.ANSI_YELLOW,
-                        "$type Dependencies Changed $projectPath for configuration \"$configurationName\":"
+                        dependenciesChangedMessage
                     )
                 )
                 difference.lines().forEach {
@@ -45,8 +42,8 @@ internal object DependencyListDiff {
                     ColorTerminal.printlnColor(
                         ColorTerminal.ANSI_RED,
                         """
-                        $type Dependencies Changed in $projectPath for configuration "$configurationName"
-                        If this is intentional, re-baseline using $projectPath:${DependencyGuardPlugin.DEPENDENCY_GUARD_BASELINE_TASK_NAME}
+                        $dependenciesChangedMessage
+                        If this is intentional, re-baseline using ./gradlew ${getQualifiedBaselineTaskForProjectPath(projectPath)}
                         """.trimIndent()
                     )
                 )

dependency-guard/src/test/kotlin/com/dropbox/gradle/plugins/dependencyguard/internal/utils/DependencyListDiffTest.kt

@@ -0,0 +1,74 @@
+package com.dropbox.gradle.plugins.dependencyguard.internal.utils
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+internal class DependencyListDiffTest {
+
+    @Test
+    fun performDiffTestRootProject() {
+        val errorSb = StringBuilder()
+
+        DependencyListDiff.performDiff(
+            projectPath = ":",
+            configurationName = "classpath",
+            expectedDependenciesFileContent = """
+            :sample:module2
+            androidx.activity:activity:1.3.1
+            """.trimIndent(),
+            actualDependenciesFileContent = """
+            :sample:module2
+            androidx.activity:activity:1.4.0
+            """.trimIndent(),
+            errorHandler = { errorSb.append(it) }
+        )
+
+        val actual = errorSb.toString()
+        val expected = """
+            Dependencies Changed in ":" for configuration "classpath"
+            - androidx.activity:activity:1.3.1
+            + androidx.activity:activity:1.4.0
+
+            Dependencies Changed in ":" for configuration "classpath"
+            If this is intentional, re-baseline using ./gradlew :dependencyGuardBaseline
+
+            """.trimIndent()
+
+        assertThat(actual)
+            .isEqualTo(expected)
+    }
+
+    @Test
+    fun performDiffTestModule() {
+        val errorSb = StringBuilder()
+
+        DependencyListDiff.performDiff(
+            projectPath = ":sample:app",
+            configurationName = "classpath",
+            expectedDependenciesFileContent = """
+            :sample:module2
+            androidx.activity:activity:1.3.1
+            """.trimIndent(),
+            actualDependenciesFileContent = """
+            :sample:module2
+            androidx.activity:activity:1.4.0
+            """.trimIndent(),
+            errorHandler = { errorSb.append(it) }
+        )
+
+        val actual = errorSb.toString()
+        val expected = """
+            Dependencies Changed in ":sample:app" for configuration "classpath"
+            - androidx.activity:activity:1.3.1
+            + androidx.activity:activity:1.4.0
+
+            Dependencies Changed in ":sample:app" for configuration "classpath"
+            If this is intentional, re-baseline using ./gradlew :sample:app:dependencyGuardBaseline
+
+            """.trimIndent()
+
+        assertThat(actual)
+            .isEqualTo(expected)
+    }
+
+}