diff --git a/data_resource_api/app/utils/descriptor.py b/data_resource_api/app/utils/descriptor.py
index 8e6c386..b60d203 100644
--- a/data_resource_api/app/utils/descriptor.py
+++ b/data_resource_api/app/utils/descriptor.py
@@ -80,10 +80,12 @@ def _create_descriptor(self, schema_dir: str, file_name: str):
                 try:
                     descriptor_dict = json.load(fh)
                 except ValueError:
-                    logger.info(
+                    raise RuntimeError(
                         f"Failed to load JSON file. JSON is probably invalid in file '{os.path.join(schema_dir, file_name)}'"
                     )
 
+        except RuntimeError:
+            raise
         except Exception:
             raise RuntimeError(f"Error opening schema {file_name}")
 
diff --git a/tests/descriptor_util_classes/test_descriptor_from_file.py b/tests/descriptor_util_classes/test_descriptor_from_file.py
index 1a8f8a7..94810d7 100644
--- a/tests/descriptor_util_classes/test_descriptor_from_file.py
+++ b/tests/descriptor_util_classes/test_descriptor_from_file.py
@@ -1,20 +1,56 @@
-from tests.schemas import frameworks_descriptor
+import json
+import os
+import shutil
 
 import pytest
-from data_resource_api.app.utils.descriptor import DescriptorFromFile
-from expects import equal, expect
+from data_resource_api.app.utils.descriptor import (
+    DescriptorFromFile,
+    DescriptorsFromDirectory,
+)
 
+IO_TEST_FILES = os.path.join(os.path.dirname(__file__), "..", "io_test_files")
+INVALID_JSON = os.path.join(IO_TEST_FILES, "invalid_json.json")
 
-@pytest.mark.skip
-def test_check_if_the_file_is_a_directory(self):
-    pass
 
+def test_raises_on_invalid_json():
+    """DescriptorFromFile must raise RuntimeError for invalid JSON, not crash with NameError."""
+    schema_dir = os.path.dirname(INVALID_JSON)
+    file_name = os.path.basename(INVALID_JSON)
+    with pytest.raises(RuntimeError, match="JSON is probably invalid"):
+        DescriptorFromFile(schema_dir, file_name)
 
-@pytest.mark.skip
-def test_test_get_only_json_files(self):
-    pass
 
+def test_raises_on_directory_instead_of_file(tmp_path):
+    """DescriptorFromFile must raise RuntimeError when given a directory path."""
+    subdir = tmp_path / "subdir"
+    subdir.mkdir()
+    with pytest.raises(RuntimeError, match="Cannot open a directory"):
+        DescriptorFromFile(str(tmp_path), "subdir")
 
-@pytest.mark.skip
-def test_returns_correctly(self):
-    pass
+
+def test_skips_invalid_json_and_continues(tmp_path):
+    """DescriptorsFromDirectory must skip invalid JSON files and keep loading valid ones."""
+    shutil.copy(INVALID_JSON, tmp_path / "invalid_json.json")
+
+    valid_descriptor = {
+        "api": {
+            "resource": "frameworks",
+            "methods": [{"get": {"enabled": True, "secured": False, "grants": []}}],
+        },
+        "datastore": {
+            "tablename": "frameworks",
+            "restricted_fields": [],
+            "schema": {
+                "fields": [
+                    {"name": "id", "type": "integer", "title": "id", "required": False}
+                ],
+                "primaryKey": "id",
+            },
+        },
+    }
+    with open(tmp_path / "valid_descriptor.json", "w") as f:
+        json.dump(valid_descriptor, f)
+
+    descriptors = list(DescriptorsFromDirectory([str(tmp_path)]).iter_files())
+    assert len(descriptors) == 1
+    assert descriptors[0].table_name == "frameworks"