1 files changed, 41 insertions, 0 deletions
diff --git a/layout/style/test/browser_sourcemap.js b/layout/style/test/browser_sourcemap.js
new file mode 100644
index 0000000000..56ad067818
--- /dev/null
+++ b/layout/style/test/browser_sourcemap.js
@@ -0,0 +1,41 @@
+add_task(async function () {
+  let uri = "http://example.com/browser/layout/style/test/sourcemap_css.html";
+  info(`URI is ${uri}`);
+
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: uri,
+    },
+    async function (browser) {
+      await SpecialPowers.spawn(browser, [], function () {
+        let seenSheets = 0;
+
+        for (let i = 0; i < content.document.styleSheets.length; ++i) {
+          let sheet = content.document.styleSheets[i];
+
+          info(`Checking ${sheet.href}`);
+          if (/mapped\.css/.test(sheet.href)) {
+            is(
+              sheet.sourceMapURL,
+              "mapped.css.map",
+              "X-SourceMap header took effect"
+            );
+            seenSheets |= 1;
+          } else if (/mapped2\.css/.test(sheet.href)) {
+            is(
+              sheet.sourceMapURL,
+              "mapped2.css.map",
+              "SourceMap header took effect"
+            );
+            seenSheets |= 2;
+          } else {
+            ok(false, "sheet does not have source map URL");
+          }
+        }
+
+        is(seenSheets, 3, "seen all source-mapped sheets");
+      });
+    }
+  );
+});