Add pytest for fetching example models and configs

Author: vloncar

hls4ml/utils/example_models.py

@@ -156,6 +156,7 @@ def fetch_example_model(model_name, backend='Vivado'):
 
     if _config_is_available(model_name):
         config = _load_example_config(model_name)
+        config[model_config] = model_name  # Ensure that paths are correct
     else:
         config = _create_default_config(model_name, model_config, backend)
 

test/pytest/test_fetch_example.py

@@ -0,0 +1,32 @@
+import ast
+import io
+from contextlib import redirect_stdout
+from pathlib import Path
+
+import pytest
+
+import hls4ml
+
+test_root_path = Path(__file__).parent
+
+
+@pytest.mark.parametrize('backend', ['Vivado', 'Vitis', 'Quartus'])
+def test_fetch_example_utils(backend):
+    f = io.StringIO()
+    with redirect_stdout(f):
+        hls4ml.utils.fetch_example_list()
+    out = f.getvalue()
+
+    model_list = ast.literal_eval(out)  # Check if we indeed got a dictionary back
+
+    assert 'qkeras_mnist_cnn.json' in model_list['keras']
+
+    # This model has an example config that is also downloaded. Stored configurations don't set "Backend" value.
+    config = hls4ml.utils.fetch_example_model('qkeras_mnist_cnn.json', backend=backend)
+    config['KerasJson'] = 'qkeras_mnist_cnn.json'
+    config['KerasH5']
+    config['Backend'] = backend
+    config['OutputDir'] = str(test_root_path / f'hls4mlprj_fetch_example_{backend}')
+
+    hls_model = hls4ml.converters.keras_to_hls(config)
+    hls_model.compile()  # For now, it is enough if it compiles, we're only testing downloading works as expected