Python test coverage now at 100%

Author: forman

chartlets.py/tests/components/charts/vega_no_altair_test.py

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+import importlib
+import pathlib
+import sys
+
+import pytest
+
+
+def test_no_altair(monkeypatch: pytest.MonkeyPatch):
+    """Test that the VegaChart component handles the absense
+    of "altair" gracefully.
+    """
+    project_root = pathlib.Path(__file__).absolute().parent
+    while project_root.parent != project_root and not (project_root / "chartlets" / "__init__.py").exists():
+        project_root = project_root.parent
+
+    # Simulate the absence of the 'altair' module
+    print("project_root:", project_root)
+    monkeypatch.setattr(sys, "path", [f"{project_root}"])
+    if "altair" in sys.modules:
+        monkeypatch.delitem(sys.modules,"altair")
+
+    # Import the code that handles the missing "altair" package
+    importlib.invalidate_caches()
+    vega_module = importlib.import_module("chartlets.components.charts.vega")
+    importlib.reload(vega_module)
+
+    # Assert "chartlets.components.charts.vega" handles the
+    # missing package appropriately by using an "altair" dummy.
+    altair = vega_module.altair
+    assert altair is not None
+    assert altair.Chart is int