diff --git a/apps/chrome-extension/src/shared/webrtc.test.ts b/apps/chrome-extension/src/shared/webrtc.test.ts
index 8bbcc249ce..1461d556ee 100644
--- a/apps/chrome-extension/src/shared/webrtc.test.ts
+++ b/apps/chrome-extension/src/shared/webrtc.test.ts
@@ -50,3 +50,26 @@ describe("waitForIceGatheringComplete", () => {
 		);
 	});
 });
+
+describe("toSessionDescriptionInit", () => {
+	it("formats valid RTCSessionDescription to RTCSessionDescriptionInit", async () => {
+		const { toSessionDescriptionInit } = await import("./webrtc");
+		const desc = {
+			type: "offer" as RTCSdpType,
+			sdp: "v=0\r\no=- 123456 2 IN IP4 127.0.0.1\r\n",
+			toJSON: () => ({}),
+		};
+		expect(toSessionDescriptionInit(desc as RTCSessionDescription)).toEqual({
+			type: "offer",
+			sdp: "v=0\r\no=- 123456 2 IN IP4 127.0.0.1\r\n",
+		});
+	});
+
+	it("throws error when session description is null or undefined", async () => {
+		const { toSessionDescriptionInit } = await import("./webrtc");
+		expect(() => toSessionDescriptionInit(null)).toThrow(
+			"Missing session description",
+		);
+	});
+});
+
diff --git a/packages/recorder-core/__tests__/recorder-utils.test.ts b/packages/recorder-core/__tests__/recorder-utils.test.ts
index 2c8da9b20f..51704559ae 100644
--- a/packages/recorder-core/__tests__/recorder-utils.test.ts
+++ b/packages/recorder-core/__tests__/recorder-utils.test.ts
@@ -198,3 +198,34 @@ describe("openShareUrlInNewTab", () => {
 		expect(openShareUrlInNewTab("")).toBe(false);
 	});
 });
+
+describe("detectRecordingModeFromTrack", () => {
+	it("returns null when track is null", async () => {
+		const { detectRecordingModeFromTrack } = await import(
+			"@cap/recorder-core/recorder-utils"
+		);
+		expect(detectRecordingModeFromTrack(null)).toBeNull();
+	});
+
+	it("detects fullscreen, window, and tab from track label heuristics", async () => {
+		const { detectRecordingModeFromTrack } = await import(
+			"@cap/recorder-core/recorder-utils"
+		);
+		const screenTrack = {
+			label: "Entire Screen 1",
+			getSettings: () => ({}),
+		} as unknown as MediaStreamTrack;
+		const windowTrack = {
+			label: "Application Window (Cap)",
+			getSettings: () => ({}),
+		} as unknown as MediaStreamTrack;
+		const tabTrack = {
+			label: "Browser Tab - YouTube",
+			getSettings: () => ({}),
+		} as unknown as MediaStreamTrack;
+
+		expect(detectRecordingModeFromTrack(screenTrack)).toBe("fullscreen");
+		expect(detectRecordingModeFromTrack(windowTrack)).toBe("window");
+		expect(detectRecordingModeFromTrack(tabTrack)).toBe("tab");
+	});
+});