From f30edbaafe6b3a88bd4e44a20713eb8c4c864cec Mon Sep 17 00:00:00 2001
From: Paul Gschwendtner <paulgschwendtner@gmail.com>
Date: Tue, 31 Dec 2019 13:51:10 +0100
Subject: [PATCH] build: create script that simplifies bazel testing workflow

Instead of remembering what individual browser targets are called,
and what the convention for Bazel labels is, we should just provide
a script that simplifies the Bazel testing workflow. e.g.

```bash
yarn test button [--local] [--firefox] [--no-watch]

yarn test src/material/button src/cdk/bidi
yarn test button slider coercion
```

Eventually we should document this script better in one of the
contributing markdown files, but these docs need a general cleanup
since they still mention Gulp.
---
 package.json                   |   5 +-
 scripts/run-component-tests.js | 107 +++++++++++++++++++++++++++++++++
 tools/defaults.bzl             |   2 +
 3 files changed, 112 insertions(+), 2 deletions(-)
 create mode 100644 scripts/run-component-tests.js

diff --git a/package.json b/package.json
index 76cba09fc997..8a6259889978 100644
--- a/package.json
+++ b/package.json
@@ -18,8 +18,9 @@
     "bazel:buildifier": "find . -type f \\( -name \"*.bzl\" -or -name WORKSPACE -or -name BUILD -or -name BUILD.bazel \\) ! -path \"*/node_modules/*\" | xargs buildifier -v --warnings=attr-cfg,attr-license,attr-non-empty,attr-output-default,attr-single-file,constant-glob,ctx-args,depset-iteration,depset-union,dict-concatenation,duplicated-name,filetype,git-repository,http-archive,integer-division,load,load-on-top,native-build,native-package,output-group,package-name,package-on-top,redefined-variable,repository-name,same-origin-load,string-iteration,unused-variable,unsorted-dict-items,out-of-order-load",
     "bazel:format-lint": "yarn -s bazel:buildifier --lint=warn --mode=check",
     "dev-app": "ibazel run //src/dev-app:devserver",
-    "test": "bazel test //src/... --test_tag_filters=-e2e,-browser:firefox-local --build_tag_filters=-browser:firefox-local --build_tests_only",
-    "test-firefox": "bazel test //src/... --test_tag_filters=-e2e,-browser:chromium-local --build_tag_filters=-browser:chromium-local --build_tests_only",
+    "test": "node ./scripts/run-component-tests.js",
+    "test-local": "yarn -s test --local",
+    "test-firefox": "yarn -s test --firefox",
     "lint": "yarn -s tslint && yarn -s bazel:format-lint && yarn -s ownerslint",
     "e2e": "bazel test //src/... --test_tag_filters=e2e",
     "deploy-dev-app": "node ./scripts/deploy-dev-app.js",
diff --git a/scripts/run-component-tests.js b/scripts/run-component-tests.js
new file mode 100644
index 000000000000..85cf9ff0536b
--- /dev/null
+++ b/scripts/run-component-tests.js
@@ -0,0 +1,107 @@
+#!/usr/bin/env node
+
+/**
+ * Script that simplifies the workflow of running unit tests for a component
+ * using Bazel. Here are a few examples:
+ *
+ *   node ./scripts/run-component-tests button            | Runs Material button tests
+ *   node ./scripts/run-component-tests overlay           | Runs CDK overlay tests
+ *   node ./scripts/run-component-tests src/cdk/a11y      | Runs CDK a11y tests
+ *   node ./scripts/run-component-tests a11y overlay      | Runs CDK a11y and overlay tests
+ *
+ * Supported command line flags:
+ *
+ *   --local    | If specified, no browser will be launched.
+ *   --firefox  | Instead of Chrome being used for tests, Firefox will be used.
+ *   --no-watch | Watch mode is enabled by default. This flag opts-out to standard Bazel.
+ */
+
+const minimist = require('minimist');
+const shelljs = require('shelljs');
+const chalk = require('chalk');
+const path = require('path');
+const args = process.argv.slice(2);
+
+// Path to the project directory.
+const projectDir = path.join(__dirname, '../');
+
+// Path to the directory that contains all packages.
+const packagesDir = path.join(projectDir, 'src/');
+
+// List of packages where the specified component could be defined in. The script uses the
+// first package that contains the component (if no package is specified explicitly).
+// e.g. "button" will become "material/button", and "overlay" becomes "cdk/overlay".
+const orderedGuessPackages = ['material', 'cdk', 'material-experimental', 'cdk-experimental'];
+
+// ShellJS should exit if any command fails.
+shelljs.set('-e');
+shelljs.cd(projectDir);
+
+// Extracts the supported command line options.
+const {_: components, local, firefox, watch} = minimist(args, {
+  boolean: ['local', 'firefox', 'watch'],
+  default: {watch: true},
+});
+
+// Exit if no component has been specified.
+if (!components.length) {
+  console.error(chalk.red(
+      'No component specified. Specify a component name, or pass a ' +
+      'path to the component directory.'));
+  process.exit(1);
+}
+
+// We can only run a single target with "--local". Running multiple targets within the
+// same Karma server is not possible since each test target runs isolated from the others.
+if (local && components.length > 1) {
+  console.error(chalk.red(
+      'Unable to run multiple components tests in local mode. ' +
+      'Only one component at a time can be run with "--local"'));
+  process.exit(1);
+}
+
+const bazelBinary = watch ? 'ibazel' : 'bazel';
+const bazelAction = local ? 'run' : 'test';
+const testTargetName =
+    `unit_tests_${local ? 'local' : firefox ? 'firefox-local' : 'chromium-local'}`;
+const testLabels = components.map(t => `${getBazelPackageOfComponentName(t)}:${testTargetName}`);
+
+// Runs Bazel for the determined test labels.
+shelljs.exec(`yarn -s ${bazelBinary} ${bazelAction} ${testLabels.join(' ')}`);
+
+/**
+ * Gets the Bazel package label for the specified component name. Throws if
+ * the component could not be resolved to a Bazel package.
+ */
+function getBazelPackageOfComponentName(name) {
+  // Before guessing any Bazel package, we test if the name contains the
+  // package name already. If so, we just use that for Bazel package.
+  const targetName = convertPathToBazelLabel(name);
+  if (targetName !== null) {
+    return targetName;
+  }
+  // If the name does not contain an explicit package name, we try guessing the
+  // package name by walking through an ordered list of possible packages and checking
+  // if a package contains a component with the given name. The first match will be used.
+  for (let guessPackage of orderedGuessPackages) {
+    const guessTargetName = convertPathToBazelLabel(path.join(packagesDir, guessPackage, name));
+    if (guessTargetName !== null) {
+      return guessTargetName;
+    }
+  }
+  throw Error(chalk.red(`Could not find test target for specified component: ` +
+    `${chalk.yellow(name)}. Looked in packages: ${orderedGuessPackages.join(', ')}`));
+}
+
+/** Converts a path to a Bazel label. */
+function convertPathToBazelLabel(name) {
+  if (shelljs.test('-d', name)) {
+    return `//${convertPathToPosix(path.relative(projectDir, name))}`;
+  }
+  return null;
+}
+
+/** Converts an arbitrary path to a Posix path. */
+function convertPathToPosix(pathName) {
+  return pathName.replace(/\\/g, '/');
+}
diff --git a/tools/defaults.bzl b/tools/defaults.bzl
index ef32f6fa94e1..72cc28d44dce 100644
--- a/tools/defaults.bzl
+++ b/tools/defaults.bzl
@@ -243,6 +243,8 @@ def ng_web_test_suite(deps = [], static_css = [], bootstrap = [], tags = [], **k
             "//test:angular_test_init",
         ] + deps,
         browsers = [
+            # Note: when changing the browser names here, also update the "yarn test"
+            # script to reflect the new browser names.
             "@io_bazel_rules_webtesting//browsers:chromium-local",
             "@io_bazel_rules_webtesting//browsers:firefox-local",
         ],