Add integration tests

Tests if repository json files conform to the json schema.
If all resources (images/icons/website URLs) they mention actually
exists.

And can also test writing images and the FAT modification code.

tests/test_schema.py

@@ -0,0 +1,28 @@
+import os
+import json
+import pytest
+from jsonschema import validate
+from jsonschema.exceptions import ValidationError
+
+
+def test_os_list_json_against_schema(oslisttuple, schema):
+    oslisturl = oslisttuple[0]
+    oslistdata = oslisttuple[1]
+    errorMsg = ""
+
+    j = json.loads(oslistdata)
+
+    try:
+        validate(instance=j, schema=schema)
+    except ValidationError as err:
+        errorMsg = err.message
+
+    if errorMsg != "":
+        pytest.fail(oslisturl+" failed schema validation: "+errorMsg, False)
+
+
+@pytest.fixture
+def schema():
+    f = open(os.path.dirname(__file__)+"/../doc/json-schema/os-list-schema.json","r")
+    data = f.read()
+    return json.loads(data)