1 files changed, 77 insertions, 0 deletions
diff --git a/dom/console/tests/xpcshell/test_formatting.js b/dom/console/tests/xpcshell/test_formatting.js
new file mode 100644
index 0000000000..89d5a1947e
--- /dev/null
+++ b/dom/console/tests/xpcshell/test_formatting.js
@@ -0,0 +1,77 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function () {
+  Assert.ok("console" in this);
+
+  const tests = [
+    // Plain value.
+    [[42], ["42"]],
+
+    // Integers.
+    [["%d", 42], ["42"]],
+    [["%i", 42], ["42"]],
+    [["c%iao", 42], ["c42ao"]],
+
+    // Floats.
+    [["%2.4f", 42], ["42.0000"]],
+    [["%2.2f", 42], ["42.00"]],
+    [["%1.2f", 42], ["42.00"]],
+    [["a%3.2fb", 42], ["a42.00b"]],
+    [["%f", NaN], ["NaN"]],
+
+    // Strings
+    [["%s", 42], ["42"]],
+
+    // Empty values.
+    [
+      ["", 42],
+      ["", "42"],
+    ],
+    [
+      ["", 42],
+      ["", "42"],
+    ],
+  ];
+
+  let p = new Promise(resolve => {
+    let t = 0;
+
+    function consoleListener() {
+      addConsoleStorageListener(this);
+    }
+
+    consoleListener.prototype = {
+      observe(aSubject) {
+        let test = tests[t++];
+
+        let obj = aSubject.wrappedJSObject;
+        Assert.equal(
+          obj.arguments.length,
+          test[1].length,
+          "Same number of arguments"
+        );
+        for (let i = 0; i < test[1].length; ++i) {
+          Assert.equal(
+            "" + obj.arguments[i],
+            test[1][i],
+            "Message received: " + test[1][i]
+          );
+        }
+
+        if (t === tests.length) {
+          removeConsoleStorageListener(this);
+          resolve();
+        }
+      },
+    };
+
+    new consoleListener();
+  });
+
+  tests.forEach(test => {
+    console.log(...test[0]);
+  });
+
+  await p;
+});