added new graph metrics

tests/render/test_import.py

@@ -0,0 +1,54 @@
+import builtins
+import importlib.util
+from importlib import reload
+
+import pytest
+
+from lang_main.errors import DependencyMissingError
+
+
+@pytest.fixture(scope='function')
+def no_dep(monkeypatch):
+    import_orig = builtins.__import__
+
+    def mocked_import(name, globals, locals, fromlist, level):
+        if name == 'py4cytoscape':
+            raise ImportError()
+        return import_orig(name, locals, fromlist, level)
+
+    monkeypatch.setattr(builtins, '__import__', mocked_import)
+
+
+@pytest.fixture(scope='function')
+def patch_find_spec(monkeypatch):
+    find_spec_orig = importlib.util.find_spec
+
+    def mocked_find_spec(*args, **kwargs):
+        if args[0] == 'py4cytoscape':
+            return None
+        else:
+            return find_spec_orig(*args, **kwargs)
+
+    monkeypatch.setattr(importlib.util, 'find_spec', mocked_find_spec)
+
+
+def test_p4c_available():
+    import lang_main.constants
+
+    reload(lang_main.constants)
+
+    assert lang_main.constants.Dependencies.PY4C.value
+
+
+@pytest.mark.usefixtures('patch_find_spec')
+def test_p4c_missing(monkeypatch):
+    import lang_main.constants
+
+    reload(lang_main.constants)
+
+    assert not lang_main.constants.Dependencies.PY4C.value
+
+    with pytest.raises(DependencyMissingError):
+        from lang_main import render
+
+        reload(render)