Merge pull request #820 from LalatenduMohanty/update_test_graph

Adding tests to test_graph to improve the coverage

Author: mergify[bot]

tests/test_graph.py

@@ -149,6 +149,161 @@ def test_get_install_dependencies():
     assert install_nodes == ["a==2.0", "d==6.0", "b==3.0", "e==6.0"]
 
 
+def test_graph_add_dependency_with_constraint():
+    """Test that constraints are properly stored in dependency nodes."""
+    graph = dependency_graph.DependencyGraph()
+
+    # Add top-level dependency with constraint
+    graph.add_dependency(
+        parent_name=None,
+        parent_version=None,
+        req_type=requirements_file.RequirementType.INSTALL,
+        req=Requirement("package-a>=1.0"),
+        req_version=Version("2.0"),
+        download_url="url",
+        constraint="package-a>=1.0,<3.0",
+    )
+
+    # Verify constraint is stored
+    node = graph.nodes["package-a==2.0"]
+    assert node.constraint == "package-a>=1.0,<3.0"
+
+    # Add child dependency with its own constraint
+    graph.add_dependency(
+        parent_name=canonicalize_name("package-a"),
+        parent_version=Version("2.0"),
+        req_type=requirements_file.RequirementType.INSTALL,
+        req=Requirement("package-b>=2.0"),
+        req_version=Version("2.5.0"),
+        download_url="url-b",
+        constraint="package-b>=2.0,<3.0",
+    )
+
+    # Verify child constraint is stored
+    child_node = graph.nodes["package-b==2.5.0"]
+    assert child_node.constraint == "package-b>=2.0,<3.0"
+
+
+def test_graph_constraint_serialization():
+    """Test that constraints survive to_dict/from_dict roundtrip."""
+    graph = dependency_graph.DependencyGraph()
+
+    # Add dependencies with various constraints
+    graph.add_dependency(
+        parent_name=None,
+        parent_version=None,
+        req_type=requirements_file.RequirementType.TOP_LEVEL,
+        req=Requirement("pkg-with-constraint"),
+        req_version=Version("1.5.0"),
+        download_url="url",
+        constraint="pkg-with-constraint>=1.0,<2.0",
+    )
+
+    graph.add_dependency(
+        parent_name=canonicalize_name("pkg-with-constraint"),
+        parent_version=Version("1.5.0"),
+        req_type=requirements_file.RequirementType.INSTALL,
+        req=Requirement("dependency-pkg"),
+        req_version=Version("3.0.0"),
+        download_url="url-dep",
+        constraint="dependency-pkg==3.0.0",
+    )
+
+    # Add dependency without constraint
+    graph.add_dependency(
+        parent_name=canonicalize_name("pkg-with-constraint"),
+        parent_version=Version("1.5.0"),
+        req_type=requirements_file.RequirementType.BUILD_SYSTEM,
+        req=Requirement("build-pkg"),
+        req_version=Version("1.0.0"),
+        download_url="url-build",
+    )
+
+    # Serialize and deserialize
+    graph_dict = graph._to_dict()
+    restored_graph = dependency_graph.DependencyGraph.from_dict(graph_dict)
+
+    # Verify constraints are preserved
+    node1 = restored_graph.nodes["pkg-with-constraint==1.5.0"]
+    assert node1.constraint == "pkg-with-constraint>=1.0,<2.0"
+
+    node2 = restored_graph.nodes["dependency-pkg==3.0.0"]
+    assert node2.constraint == "dependency-pkg==3.0.0"
+
+    # Verify empty constraint is preserved
+    node3 = restored_graph.nodes["build-pkg==1.0.0"]
+    assert node3.constraint == ""
+
+
+def test_graph_duplicate_node_constraint_behavior():
+    """Test behavior when same package is added with different constraints.
+
+    When a node with the same key (name==version) is added multiple times,
+    the first node is reused, including its constraint value.
+    """
+    graph = dependency_graph.DependencyGraph()
+
+    # Add package with first constraint
+    graph.add_dependency(
+        parent_name=None,
+        parent_version=None,
+        req_type=requirements_file.RequirementType.INSTALL,
+        req=Requirement("shared-pkg>=1.0"),
+        req_version=Version("2.0"),
+        download_url="url1",
+        constraint="shared-pkg>=1.0,<3.0",
+    )
+
+    # Add another toplevel
+    graph.add_dependency(
+        parent_name=None,
+        parent_version=None,
+        req_type=requirements_file.RequirementType.INSTALL,
+        req=Requirement("other-pkg"),
+        req_version=Version("1.0"),
+        download_url="url2",
+    )
+
+    # Add same package as dependency with different constraint
+    graph.add_dependency(
+        parent_name=canonicalize_name("other-pkg"),
+        parent_version=Version("1.0"),
+        req_type=requirements_file.RequirementType.INSTALL,
+        req=Requirement("shared-pkg>=2.0"),
+        req_version=Version("2.0"),
+        download_url="url1",
+        constraint="shared-pkg>=2.0,<4.0",  # Different constraint
+    )
+
+    # The first constraint should be retained (existing node is reused)
+    node = graph.nodes["shared-pkg==2.0"]
+    assert node.constraint == "shared-pkg>=1.0,<3.0"
+
+    # Verify both parents exist
+    assert len(node.parents) == 2
+
+
+def test_graph_constraint_in_to_dict():
+    """Test that to_dict() includes constraint information."""
+    graph = dependency_graph.DependencyGraph()
+
+    graph.add_dependency(
+        parent_name=None,
+        parent_version=None,
+        req_type=requirements_file.RequirementType.TOP_LEVEL,
+        req=Requirement("test-pkg"),
+        req_version=Version("1.0.0"),
+        download_url="https://example.com/test-pkg.tar.gz",
+        constraint="test-pkg>=1.0,<2.0",
+    )
+
+    graph_dict = graph._to_dict()
+
+    # Verify constraint is in the serialized format
+    assert "test-pkg==1.0.0" in graph_dict
+    assert graph_dict["test-pkg==1.0.0"]["constraint"] == "test-pkg>=1.0,<2.0"
+
+
 def test_cycles_get_install_dependencies():
     graph = dependency_graph.DependencyGraph.from_dict(raw_graph)
     # create cycle: a depends on d and d depends on a