Fix #2937: Ensure the consistency in load_dotenv's return type

tests/test_cli.py

@@ -513,7 +513,7 @@ def test_load_dotenv(monkeypatch):
 
     monkeypatch.setenv("EGGS", "3")
     monkeypatch.chdir(os.path.join(test_path, "cliapp", "inner1"))
-    load_dotenv()
+    assert load_dotenv()
     assert os.getcwd() == test_path
     # .flaskenv doesn't overwrite .env
     assert os.environ["FOO"] == "env"
@@ -524,6 +524,9 @@ def test_load_dotenv(monkeypatch):
     # set manually, files don't overwrite
     assert os.environ["EGGS"] == "3"
 
+    # Non existent file should not load
+    assert not load_dotenv('non-existent-file')
+
 
 @need_dotenv
 def test_dotenv_path(monkeypatch):