test: 💍 add a test about the cache reports

tests/test_cache_reports.py

@@ -0,0 +1,28 @@
+from datasets_preview_backend.cache_reports import get_kwargs_report
+from datasets_preview_backend.config import CACHE_DIRECTORY, CACHE_PERSIST
+from datasets_preview_backend.responses import get_cached_response
+
+
+def test_cache_directory() -> None:
+    # ensure the cache directory is empty, so that this file gets an empty cache
+    assert CACHE_DIRECTORY is None
+    assert not CACHE_PERSIST
+    # note that the same cache is used all over this file. We might want to call
+    # http://www.grantjenks.com/docs/diskcache/api.html#diskcache.Cache.clear
+    # at the beginning of every test to start with an empty cache
+
+
+def test_get_kwargs_report_error() -> None:
+    endpoint = "/configs"
+    kwargs = {"dataset": "doesnotexist"}
+
+    report = get_kwargs_report(endpoint, kwargs)
+    assert report["status"] == "cache_miss"
+
+    # warm the cache
+    get_cached_response(endpoint, **kwargs)
+    report = get_kwargs_report(endpoint, kwargs)
+    assert report["status"] == "error"
+
+    report = get_kwargs_report(endpoint, kwargs)
+    assert report["status"] == "error"