1 files changed, 44 insertions, 0 deletions
diff --git a/toolkit/components/glean/gtest/test.rs b/toolkit/components/glean/gtest/test.rs
new file mode 100644
index 0000000000..27af068734
--- /dev/null
+++ b/toolkit/components/glean/gtest/test.rs
@@ -0,0 +1,44 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+fn nonfatal_fail(msg: String) {
+    extern "C" {
+        fn GTest_FOG_ExpectFailure(message: *const ::std::os::raw::c_char);
+    }
+    unsafe {
+        let msg = ::std::ffi::CString::new(msg).unwrap();
+        GTest_FOG_ExpectFailure(msg.as_ptr());
+    }
+}
+
+/// This macro checks if the expression evaluates to true,
+/// and causes a non-fatal GTest test failure if it doesn't.
+macro_rules! expect {
+    ($x:expr) => {
+        match (&$x) {
+            true => {}
+            false => nonfatal_fail(format!(
+                "check failed: (`{}`) at {}:{}",
+                stringify!($x),
+                file!(),
+                line!()
+            )),
+        }
+    };
+}
+
+#[no_mangle]
+pub extern "C" fn Rust_MeasureInitializeTime() {
+    // At this point FOG is already initialized.
+    // We still need for it to finish, as it is running in a separate thread.
+
+    let metric = &*fog::metrics::fog::initialization;
+    while metric.test_get_value("metrics").is_none() {
+        // We _know_ this value is recorded early, so let's just yield
+        // and try again quickly.
+        std::thread::yield_now();
+    }
+
+    let value = metric.test_get_value("metrics").unwrap();
+    expect!(value > 0);
+}