From a2dc4546e8a2936d56cc4caa56b2fd8dc821206f Mon Sep 17 00:00:00 2001
From: Connor <cwybro@users.noreply.github.com>
Date: Wed, 15 Feb 2023 19:11:18 -0500
Subject: [PATCH] Implement --test_filter support (#999)

Implement `--test_filter` support, as detailed in
https://github.com/bazelbuild/rules_swift/issues/997. This can be
engaged via a `swift_test` target like so:

```
bazel test //:Tests --test_filter=TestModuleName.TestClassName/testMethodName
```

**Note:** If `--test_filter` is not passed into the test invocation, we
fallback to the original behavior (pass `All` into the xctest
invocation.
---
 doc/rules.md                                  |  6 +++
 examples/apple/test_filter/BUILD              | 51 +++++++++++++++++++
 examples/apple/test_filter/FailTests.swift    |  8 +++
 .../apple/test_filter/PassFailTests.swift     | 12 +++++
 examples/apple/test_filter/PassTests.swift    |  8 +++
 examples/apple/test_filter/TestHelper.swift   | 20 ++++++++
 swift/internal/swift_binary_test.bzl          |  6 +++
 tools/xctest_runner/xctest_runner.sh.template |  4 +-
 8 files changed, 113 insertions(+), 2 deletions(-)
 create mode 100644 examples/apple/test_filter/BUILD
 create mode 100644 examples/apple/test_filter/FailTests.swift
 create mode 100644 examples/apple/test_filter/PassFailTests.swift
 create mode 100644 examples/apple/test_filter/PassTests.swift
 create mode 100644 examples/apple/test_filter/TestHelper.swift

diff --git a/doc/rules.md b/doc/rules.md
index 83127405d..b90520d16 100644
--- a/doc/rules.md
+++ b/doc/rules.md
@@ -499,6 +499,12 @@ have the paths made absolute via swizzling by enabling the
 set the `BUILD_WORKSPACE_DIRECTORY` environment variable in your scheme to the
 root of your workspace (i.e. `$(SRCROOT)`).
 
+A subset of tests for a given target can be executed via the `--test_filter` parameter:
+
+```
+bazel test //:Tests --test_filter=TestModuleName.TestClassName/testMethodName
+```
+
 
 **ATTRIBUTES**
 
diff --git a/examples/apple/test_filter/BUILD b/examples/apple/test_filter/BUILD
new file mode 100644
index 000000000..b45876508
--- /dev/null
+++ b/examples/apple/test_filter/BUILD
@@ -0,0 +1,51 @@
+load(
+    "//swift:swift.bzl",
+    "swift_library",
+    "swift_test",
+)
+
+swift_library(
+    name = "test_filter_lib",
+    testonly = True,
+    srcs = [
+        "FailTests.swift",
+        "PassFailTests.swift",
+        "PassTests.swift",
+        "TestHelper.swift",
+    ],
+    module_name = "test_filter",
+    target_compatible_with = ["@platforms//os:macos"],
+)
+
+# Verify that tests fail as expected without test filtering.
+swift_test(
+    name = "test_filter__baseline",
+    env = {
+        "EXPECT_FAILURE": "TRUE",
+    },
+    module_name = "test_filter",
+    target_compatible_with = ["@platforms//os:macos"],
+    deps = [":test_filter_lib"],
+)
+
+# Verify that test scope is filtered by TARGET.TEST_CLASS as expected.
+swift_test(
+    name = "test_filter__feature__target_class",
+    env = {
+        "TESTBRIDGE_TEST_ONLY": "test_filter.PassTests",
+    },
+    module_name = "test_filter",
+    target_compatible_with = ["@platforms//os:macos"],
+    deps = [":test_filter_lib"],
+)
+
+# Verify that test scope is filtered by TARGET.TEST_CLASS.TEST_METHOD as expected.
+swift_test(
+    name = "test_filter__feature__target_class_method",
+    env = {
+        "TESTBRIDGE_TEST_ONLY": "test_filter.PassFailTests/test_pass",
+    },
+    module_name = "test_filter",
+    target_compatible_with = ["@platforms//os:macos"],
+    deps = [":test_filter_lib"],
+)
diff --git a/examples/apple/test_filter/FailTests.swift b/examples/apple/test_filter/FailTests.swift
new file mode 100644
index 000000000..f6ca990c9
--- /dev/null
+++ b/examples/apple/test_filter/FailTests.swift
@@ -0,0 +1,8 @@
+import XCTest
+
+class FailTests: XCTestCase {
+
+    func test_fail() {
+        TestHelper.ExpectFailureIfNeeded()
+    }
+}
diff --git a/examples/apple/test_filter/PassFailTests.swift b/examples/apple/test_filter/PassFailTests.swift
new file mode 100644
index 000000000..cbd2d9319
--- /dev/null
+++ b/examples/apple/test_filter/PassFailTests.swift
@@ -0,0 +1,12 @@
+import XCTest
+
+class PassFailTests: XCTestCase {
+
+    func test_pass() {
+        TestHelper.Pass()
+    }
+
+    func test_fail() {
+        TestHelper.ExpectFailureIfNeeded()
+    }
+}
diff --git a/examples/apple/test_filter/PassTests.swift b/examples/apple/test_filter/PassTests.swift
new file mode 100644
index 000000000..47796d72b
--- /dev/null
+++ b/examples/apple/test_filter/PassTests.swift
@@ -0,0 +1,8 @@
+import XCTest
+
+class PassTests: XCTestCase {
+
+    func test_pass() {
+        TestHelper.Pass()
+    }
+}
diff --git a/examples/apple/test_filter/TestHelper.swift b/examples/apple/test_filter/TestHelper.swift
new file mode 100644
index 000000000..3e7b9e9d6
--- /dev/null
+++ b/examples/apple/test_filter/TestHelper.swift
@@ -0,0 +1,20 @@
+import XCTest
+
+enum TestHelper {
+
+    static func ExpectFailureIfNeeded() {
+        let options: XCTExpectedFailure.Options = .init()
+        options.isEnabled = ProcessInfo.processInfo.environment["EXPECT_FAILURE"] == "TRUE"
+        XCTExpectFailure("Expected failure", options: options) {
+            Fail()
+        }
+    }
+
+    static func Pass() {
+        XCTAssertTrue(true)
+    }
+
+    private static func Fail() {
+        XCTFail("Fail")
+    }
+}
diff --git a/swift/internal/swift_binary_test.bzl b/swift/internal/swift_binary_test.bzl
index d8646d28e..7420cf87d 100644
--- a/swift/internal/swift_binary_test.bzl
+++ b/swift/internal/swift_binary_test.bzl
@@ -532,6 +532,12 @@ have the paths made absolute via swizzling by enabling the
 `"apple.swizzle_absolute_xcttestsourcelocation"` feature. You'll also need to
 set the `BUILD_WORKSPACE_DIRECTORY` environment variable in your scheme to the
 root of your workspace (i.e. `$(SRCROOT)`).
+
+A subset of tests for a given target can be executed via the `--test_filter` parameter:
+
+```
+bazel test //:Tests --test_filter=TestModuleName.TestClassName/testMethodName
+```
 """,
     executable = True,
     fragments = ["cpp"],
diff --git a/tools/xctest_runner/xctest_runner.sh.template b/tools/xctest_runner/xctest_runner.sh.template
index 11fd254c7..a760f5786 100644
--- a/tools/xctest_runner/xctest_runner.sh.template
+++ b/tools/xctest_runner/xctest_runner.sh.template
@@ -54,8 +54,8 @@ fi
 
 exit_status=0
 xctest=$(xcrun -f xctest)
-# TODO(allevato): Support Bazel's --test_filter.
-DYLD_INSERT_LIBRARIES=$sanitizer_dyld_env LLVM_PROFILE_FILE="$profraw" $xctest -XCTest All "$bundle_path" || exit_status=$?
+test_filter=${TESTBRIDGE_TEST_ONLY:-All}
+DYLD_INSERT_LIBRARIES=$sanitizer_dyld_env LLVM_PROFILE_FILE="$profraw" $xctest -XCTest "$test_filter" "$bundle_path" || exit_status=$?
 
 if [[ "$exit_status" -ne 0 ]]; then
   exit "$exit_status"