Improve test coverage

tests/system_time_success.rs

@@ -118,4 +118,11 @@ test! {
 		assert!(later >= earlier);
 		assert!(later.duration_since(earlier).unwrap() <= MAX_DIFF);
 	}
+
+	/// [`SystemTime::elapsed()`] failure.
+	async fn error() {
+		let time = SystemTime::now() + DIFF;
+		let error = time.elapsed().unwrap_err();
+		assert_eq!(error.to_string(), "second time provided was later than self");
+	}
 }

tests/web.rs

@@ -0,0 +1,38 @@
+#![cfg(test)]
+#![cfg(target_family = "wasm")]
+
+use std::time;
+use std::time::Duration;
+
+use wasm_bindgen_test::wasm_bindgen_test;
+use web_time::web::SystemTimeExt;
+
+wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);
+
+#[wasm_bindgen_test]
+fn to_std() {
+	assert_eq!(
+		web_time::SystemTime::UNIX_EPOCH.to_std(),
+		time::SystemTime::UNIX_EPOCH,
+	);
+
+	let duration = Duration::from_secs(60 * 60 * 24 * 365);
+	assert_eq!(
+		(web_time::SystemTime::UNIX_EPOCH + duration).to_std(),
+		time::SystemTime::UNIX_EPOCH + duration,
+	);
+}
+
+#[wasm_bindgen_test]
+fn from_std() {
+	assert_eq!(
+		web_time::SystemTime::from_std(time::SystemTime::UNIX_EPOCH),
+		web_time::SystemTime::UNIX_EPOCH,
+	);
+
+	let duration = Duration::from_secs(60 * 60 * 24 * 365);
+	assert_eq!(
+		web_time::SystemTime::from_std(time::SystemTime::UNIX_EPOCH + duration),
+		web_time::SystemTime::UNIX_EPOCH + duration,
+	);
+}