1 files changed, 72 insertions, 0 deletions
diff --git a/apps/web/src/voiceover/__tests__/devices.test.ts b/apps/web/src/voiceover/__tests__/devices.test.ts
new file mode 100644
index 00000000..524e8c3f
--- /dev/null
+++ b/apps/web/src/voiceover/__tests__/devices.test.ts
@@ -0,0 +1,72 @@
+import { describe, expect, test } from "bun:test";
+import {
+	DEFAULT_AUDIO_INPUT_DEVICE_ID,
+	buildVoiceOverAudioConstraints,
+	normalizeSelectedDeviceId,
+	type VoiceOverInputDevice,
+} from "@/voiceover/devices";
+
+const devices: VoiceOverInputDevice[] = [
+	{
+		deviceId: DEFAULT_AUDIO_INPUT_DEVICE_ID,
+		label: "System default microphone",
+		isDefault: true,
+	},
+	{
+		deviceId: "blue-yeti-snowball",
+		label: "Blue Snowball",
+		isDefault: false,
+	},
+];
+
+describe("buildVoiceOverAudioConstraints", () => {
+	test("uses default processing constraints without an exact device", () => {
+		const constraints = buildVoiceOverAudioConstraints({ deviceId: null });
+		expect(constraints.audio).toEqual({
+			echoCancellation: true,
+			noiseSuppression: true,
+			autoGainControl: true,
+		});
+	});
+
+	test("adds an exact device constraint for a selected microphone", () => {
+		const constraints = buildVoiceOverAudioConstraints({
+			deviceId: "blue-yeti-snowball",
+		});
+		expect(constraints.audio).toEqual({
+			deviceId: { exact: "blue-yeti-snowball" },
+			echoCancellation: true,
+			noiseSuppression: true,
+			autoGainControl: true,
+		});
+	});
+});
+
+describe("normalizeSelectedDeviceId", () => {
+	test("keeps the selected device when it is still present", () => {
+		expect(
+			normalizeSelectedDeviceId({
+				deviceId: "blue-yeti-snowball",
+				devices,
+			}),
+		).toBe("blue-yeti-snowball");
+	});
+
+	test("clears a selected device when it is no longer present", () => {
+		expect(
+			normalizeSelectedDeviceId({
+				deviceId: "missing",
+				devices,
+			}),
+		).toBeNull();
+	});
+
+	test("keeps the browser default device id", () => {
+		expect(
+			normalizeSelectedDeviceId({
+				deviceId: DEFAULT_AUDIO_INPUT_DEVICE_ID,
+				devices: [],
+			}),
+		).toBe(DEFAULT_AUDIO_INPUT_DEVICE_ID);
+	});
+});