fix(karma): allow custom browsers to specify args (fixes #595)

.bazelci/presubmit.yml

@@ -32,7 +32,7 @@ tasks:
     # on bazelci apt-get fails with permission denied and there is no sudo
     # command to switch to root.
     # TODO(gregmagolan): figure out how to install missing shared libs
-    - "--test_tag_filters=-e2e,-examples,-manual,-browser:chromium-local,-browser:firefox-local,-cypress"
+    - "--test_tag_filters=-e2e,-examples,-manual,-browser:chromium-local,-browser:firefox-local,-browser:custom_chrome,-cypress"
     test_targets:
     - "//..."
     # //internal/node/test:nodejs_toolchain_linux_amd64_test is a "manual" test that must be run
@@ -137,7 +137,7 @@ tasks:
     # on bazelci apt-get fails with permission denied and there is no sudo
     # command to switch to root.
     # TODO(gregmagolan): figure out how to install missing shared libs
-    - "--test_tag_filters=-e2e,-examples,-manual,-browser:chromium-local,-browser:firefox-local,-cypress"
+    - "--test_tag_filters=-e2e,-examples,-manual,-browser:chromium-local,-browser:firefox-local,-browser:custom_chrome,-cypress"
     test_targets:
     - "//..."
     # //internal/node/test:nodejs_toolchain_linux_amd64_test is a "manual" test that must be run
@@ -158,7 +158,7 @@ tasks:
     # on bazelci apt-get fails with permission denied and there is no sudo
     # command to switch to root.
     # TODO(gregmagolan): figure out how to install missing shared libs
-    - "--test_tag_filters=-e2e,-examples,-manual,-browser:chromium-local,-browser:firefox-local,-cypress"
+    - "--test_tag_filters=-e2e,-examples,-manual,-browser:chromium-local,-browser:firefox-local,-browser:custom_chrome,-cypress"
     test_targets:
     - "//..."
   ubuntu1804_e2e:

internal/generated_file_test/bin.js

@@ -4,6 +4,23 @@ const path = require('path');
 import * as unidiff from 'unidiff/unidiff';
 const runfiles = require(process.env['BAZEL_NODE_RUNFILES_HELPER']);
 
+function findGoldenInGenerated(golden, actual) {
+  const goldenLines = golden.split(/[\r\n]+/g).map(l => l.trim());
+  const actualLines = actual.split(/[\r\n]+/g).map(l => l.trim());
+  // Note: this is not the fastest subsequence algorithm.
+  nextActualLine: for (let i = 0; i < actualLines.length; i++) {
+    for (let j = 0; j < goldenLines.length; j++) {
+      if (actualLines[i + j] !== goldenLines[j]) {
+        continue nextActualLine;
+      }
+    }
+    // A match!
+    return true;
+  }
+  // No match.
+  return false;
+}
+
 function main(args) {
   const [mode, golden_no_debug, golden_debug, actual] = args;
   const actualPath = runfiles.resolveWorkspaceRelative(actual);
@@ -23,7 +40,7 @@ function main(args) {
     return 0;
   }
   if (mode === '--verify') {
-    // Generated does not match golden
+    // Compare the generated file to the golden file.
     const diff = unidiff.diffLines(goldenContents, actualContents);
     let prettyDiff =
         unidiff.formatLines(diff, {aname: `[workspace]/${golden}`, bname: `[bazel-out]/${actual}`});
@@ -41,6 +58,19 @@ If the bazel-out content is correct, you can update the workspace file by runnin
 `);
     return 1;
   }
+  if (mode === '--substring') {
+    // Verify that the golden file is contained _somewhere_ in the generated
+    // file.
+    const diff = findGoldenInGenerated(goldenContents, actualContents);
+    if (diff) {
+      console.error(`Unable to find golden contents inside of the the generated file:
+
+${goldenContents}
+`)
+      return 1;
+    }
+    return 0;
+  }
   throw new Error('unknown mode', mode);
 }
 

internal/generated_file_test/generated_file_test.bzl

@@ -2,7 +2,7 @@
 
 load("@build_bazel_rules_nodejs//internal/node:node.bzl", "nodejs_binary", "nodejs_test")
 
-def generated_file_test(name, generated, src, src_dbg = None, **kwargs):
+def generated_file_test(name, generated, src, substring_search = False, src_dbg = None, **kwargs):
     """Tests that a file generated by Bazel has identical content to a file in the workspace.
 
     This is useful for testing, where a "snapshot" or "golden" file is checked in,
@@ -12,6 +12,8 @@ def generated_file_test(name, generated, src, src_dbg = None, **kwargs):
         name: Name of the rule.
         generated: a Label of the output file generated by another rule
         src: Label of the source file in the workspace
+        substring_search: When true, creates a test that will fail only if the golden file is not found
+            anywhere within the generated file. Note that the .update rule is not generated in substring mode.
         src_dbg: if the build uses `--compilation_mode dbg` then some rules will produce different output.
             In this case you can specify what the dbg version of the output should look like
         **kwargs: extra arguments passed to the underlying nodejs_test or nodejs_binary
@@ -27,16 +29,22 @@ def generated_file_test(name, generated, src, src_dbg = None, **kwargs):
     nodejs_test(
         name = name,
         entry_point = "@build_bazel_rules_nodejs//internal/generated_file_test:bundle.js",
-        templated_args = ["--verify", loc % src, loc % src_dbg, loc % generated],
+        templated_args = [
+            "--substring" if substring_search else "--verify",
+            loc % src,
+            loc % src_dbg,
+            loc % generated,
+        ],
         data = data,
         **kwargs
     )
 
-    nodejs_binary(
-        name = name + ".update",
-        testonly = True,
-        entry_point = "@build_bazel_rules_nodejs//internal/generated_file_test:bundle.js",
-        templated_args = ["--out", loc % src, loc % src_dbg, loc % generated],
-        data = data,
-        **kwargs
-    )
+    if not substring_search:
+        nodejs_binary(
+            name = name + ".update",
+            testonly = True,
+            entry_point = "@build_bazel_rules_nodejs//internal/generated_file_test:bundle.js",
+            templated_args = ["--out", loc % src, loc % src_dbg, loc % generated],
+            data = data,
+            **kwargs
+        )

packages/karma/karma.conf.js

@@ -321,13 +321,23 @@ try {
                   webTestNamedFiles['CHROMIUM']}' in runfiles`);
             }
           }
+          // Read any additional chrome options (as specified by the
+          // rules_webtesting manifest).
+          const chromeOptions = (webTestMetadata['capabilities'] || {})['goog:chromeOptions'];
+          const additionalArgs = (chromeOptions ? chromeOptions['args'] : []).filter(arg => {
+            // We never want to 'run' Chrome in headless mode.
+            return arg != '--headless';
+          });
           const browser = process.env['DISPLAY'] ? 'Chrome' : 'ChromeHeadless';
           if (!supportChromeSandboxing()) {
             const launcher = 'CustomChromeWithoutSandbox';
-            conf.customLaunchers = {[launcher]: {base: browser, flags: ['--no-sandbox']}};
+            conf.customLaunchers =
+                {[launcher]: {base: browser, flags: ['--no-sandbox', ...additionalArgs]}};
             conf.browsers.push(launcher);
           } else {
-            conf.browsers.push(browser);
+            const launcher = 'CustomChrome';
+            conf.customLaunchers = {[launcher]: {base: browser, flags: additionalArgs}};
+            conf.browsers.push(launcher);
           }
         }
         if (webTestNamedFiles['FIREFOX']) {

packages/karma/karma_web_test.bzl

@@ -120,10 +120,7 @@ def _find_dep(ctx, suffix):
 
 # Generates the karma configuration file for the rule
 def _write_karma_config(ctx, files, amd_names_shim):
-    configuration = ctx.actions.declare_file(
-        "%s.conf.js" % ctx.label.name,
-        sibling = ctx.outputs.executable,
-    )
+    configuration = ctx.outputs.configuration
 
     config_file = None
 
@@ -325,6 +322,9 @@ _karma_web_test = rule(
     test = True,
     executable = True,
     attrs = KARMA_WEB_TEST_ATTRS,
+    outputs = {
+        "configuration": "%{name}.conf.js",
+    },
 )
 
 def karma_web_test(

packages/karma/test/karma/BUILD.bazel

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+load("@build_bazel_rules_nodejs//:index.bzl", "generated_file_test")
+load("@io_bazel_rules_webtesting//web:web.bzl", "custom_browser")
 load("//packages/karma:index.bzl", "karma_web_test_suite")
 
 karma_web_test_suite(
@@ -26,6 +28,7 @@ karma_web_test_suite(
     browsers = [
         "@io_bazel_rules_webtesting//browsers:chromium-local",
         "@io_bazel_rules_webtesting//browsers:firefox-local",
+        ":custom_chrome",
     ],
     static_files = [
         "unnamed-amd-module.js",
@@ -41,3 +44,16 @@ karma_web_test_suite(
         "requirejs-config.js",
     ],
 )
+
+custom_browser(
+    name = "custom_chrome",
+    browser = "@io_bazel_rules_webtesting//browsers:chromium-local",
+    metadata = "custom_chrome.json",
+)
+
+generated_file_test(
+    name = "test_custom_chrome_karma_conf",
+    src = "karma.conf.js.golden",
+    generated = "testing_wrapped_test.conf.js",
+    substring_search = True,
+)

packages/karma/test/karma/custom_chrome.json

@@ -0,0 +1,11 @@
+{
+  "capabilities": {
+    "goog:chromeOptions": {
+      "args": [
+        "--remote-debugging-port=9222",
+        "--headless",
+        "--use-gl=swiftshader-webgl"
+      ]
+    }
+  }
+}

packages/karma/test/karma/karma.conf.js.golden

@@ -0,0 +1,5 @@
+const chromeOptions = (webTestMetadata['capabilities'] || {})['goog:chromeOptions'];
+const additionalArgs = (chromeOptions ? chromeOptions['args'] : []).filter(arg => {
+  // We never want to 'run' Chrome in headless mode.
+  return arg != '--headless';
+});