Add deterministic-tests (#190)

Reviewed-on: https://home.schmelczer.dev/git/git/andras/vault-link/pulls/190
Co-authored-by: Andras Schmelczer <andras@schmelczer.dev>
Co-committed-by: Andras Schmelczer <andras@schmelczer.dev>

frontend/deterministic-tests/src/utils/assert.ts

@@ -0,0 +1,5 @@
+export function assert(value: boolean, message: string): asserts value {
+    if (!value) {
+        throw new Error(message);
+    }
+}