55: Flag --dry-run

Sources/SelectiveTestingCore/SelectiveTestingTool.swift

@@ -18,6 +18,7 @@ public final class SelectiveTestingTool {
     private let changedFiles: [String]
     private let renderDependencyGraph: Bool
     private let turbo: Bool
+    private let dryRun: Bool
     private let dot: Bool
     private let verbose: Bool
     private let testPlan: String?
@@ -31,6 +32,7 @@ public final class SelectiveTestingTool {
                 renderDependencyGraph: Bool = false,
                 dot: Bool = false,
                 turbo: Bool = false,
+                dryRun: Bool = false,
                 verbose: Bool = false) throws
     {
         if let configData = try? (Path.current + Config.defaultConfigName).read(),
@@ -53,6 +55,7 @@ public final class SelectiveTestingTool {
         self.renderDependencyGraph = renderDependencyGraph
         self.turbo = turbo
         self.dot = dot
+        self.dryRun = dryRun
         self.verbose = verbose
         self.testPlan = testPlan ?? config?.testPlan
     }
@@ -127,11 +130,11 @@ public final class SelectiveTestingTool {
             }
         }
 
-        if let testPlan {
+        if !dryRun, let testPlan {
             // 4. Configure workspace to test given targets
             try enableTests(at: Path(testPlan),
                             targetsToTest: affectedTargets)
-        } else if let testPlan = workspaceInfo.candidateTestPlan {
+        } else if !dryRun, let testPlan = workspaceInfo.candidateTestPlan {
             try enableTests(at: Path(testPlan),
                             targetsToTest: affectedTargets)
         } else if !printJSON {

Sources/xcode-selective-test/SelectiveTesting.swift

@@ -34,6 +34,9 @@ struct SelectiveTesting: AsyncParsableCommand {
     @Flag(help: "Turbo mode: run directly affected tests only")
     var turbo: Bool = false
 
+    @Flag(help: "Dry run: do not modify the test plans")
+    var dryRun: Bool = false
+
     @Flag(help: "Produce verbose output")
     var verbose: Bool = false
 

Tests/SelectiveTestingTests/IntegrationTestTool.swift

@@ -109,6 +109,17 @@ final class IntegrationTestTool {
 
         XCTAssertEqual(Set(testPlanTargets), expected)
     }
+
+    func checkTestPlanUnmodified(at newPath: Path) throws {
+        guard let exampleInBundle = Bundle.module.path(forResource: "ExampleProject", ofType: "") else {
+            fatalError("Missing ExampleProject in TestBundle")
+        }
+        let orignialTestPlanPath = Path(exampleInBundle) + Path(newPath.lastComponent)
+        let originalContents = try String(contentsOfFile: orignialTestPlanPath.string)
+
+        let newContents = try String(contentsOfFile: newPath.string)
+        XCTAssertEqual(originalContents, newContents)
+    }
 
     lazy var mainProjectMainTarget = TargetIdentity.project(path: projectPath + "ExampleProject.xcodeproj", targetName: "ExampleProject", testTarget: false)
     lazy var mainProjectTests = TargetIdentity.project(path: projectPath + "ExampleProject.xcodeproj", targetName: "ExampleProjectTests", testTarget: true)

Tests/SelectiveTestingTests/SelectiveTestingConfigTests.swift

@@ -162,4 +162,22 @@ final class SelectiveTestingConfigTests: XCTestCase {
         try testTool.validateTestPlan(testPlanPath: testTool.projectPath + "ExampleProject.xctestplan",
                                       expected: Set([testTool.subtests]))
     }
+
+    func testDryRun() async throws {
+        // given
+        let tool = try SelectiveTestingTool(baseBranch: "main",
+                                            basePath: (testTool.projectPath + "ExampleWorkspace.xcworkspace").string,
+                                            testPlan: "ExampleProject.xctestplan",
+                                            changedFiles: [],
+                                            renderDependencyGraph: false,
+                                            dryRun: true,
+                                            verbose: true)
+
+        // when
+        try testTool.changeFile(at: testTool.projectPath + "ExamplePackage/Tests/Subtests/Test.swift")
+
+        // then
+        let _ = try await tool.run()
+        try testTool.checkTestPlanUnmodified(at: testTool.projectPath + "ExampleProject.xctestplan")
+    }
 }