1 files changed, 28 insertions, 0 deletions
diff --git a/packages/lsp/src/language.test.ts b/packages/lsp/src/language.test.ts
new file mode 100644
index 0000000..3ec4b47
--- /dev/null
+++ b/packages/lsp/src/language.test.ts
@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+import { languageId } from "./language.js";
+
+describe("language", () => {
+	it("maps .ts to typescript", () => {
+		expect(languageId("file.ts")).toBe("typescript");
+	});
+
+	it("maps .tsx to typescriptreact", () => {
+		expect(languageId("file.tsx")).toBe("typescriptreact");
+	});
+
+	it("maps .js to javascript", () => {
+		expect(languageId("file.js")).toBe("javascript");
+	});
+
+	it("maps .luau to luau", () => {
+		expect(languageId("file.luau")).toBe("luau");
+	});
+
+	it("returns unknown for unrecognized extensions", () => {
+		expect(languageId("file.xyz")).toBe("unknown");
+	});
+
+	it("returns unknown for files without extensions", () => {
+		expect(languageId("Makefile")).toBe("unknown");
+	});
+});