Refactor edge_range tests to use GoogleTest matchers and parameterized tests

[Copilot]

Refactors the edge_range tests to improve maintainability and readability by using GoogleTest matchers and converting to parameterized tests.

Changes Made

• Removed helper functions: Eliminated check_edge_range helper functions to reduce indirection
• Used GoogleTest matchers: Replaced manual assertion loops with ElementsAreArray matcher for better test output
• Pointwise matcher for edge indices: Uses Pointwise with a custom EdgeIndexMatches matcher to verify edge indices are consecutive, providing clear test logic and better error messages
• Inline vector construction: Made matcher statements more concise by using std::vector constructor inline
• Removed unnecessary conditionals: Removed CSR representation checks from edgelist tests (always false) and simplified CSR tests (always true)
• Parameterized by generator type: Converted to parameterized tests that test each graph generator (GNM, RMAT, RGG2D, RGG3D, RHG, Grid2D, Grid3D) separately

Test Coverage

The refactored test suite now generates 28 test cases (7 generators × 4 test variations):

• iterate_edgelist_representation - tests with 16*n edges using edge list representation
• iterate_sparse_edgelist_representation - tests with 2*n edges using edge list representation
• iterate_csr_representation - tests with 16*n edges using CSR representation
• iterate_sparse_csr_representation - tests with 2*n edges using CSR representation

Each test case clearly indicates which generator is being tested (e.g., EdgeRangeTests/EdgeRangeTestFixture.iterate_edgelist_representation/GNM), making test failures easier to diagnose.

Benefits

• Better maintainability: Adding a new generator requires only one line in the parameter list
• Clearer test output: Test names now include the generator type being tested, and the Pointwise matcher provides descriptive failure messages
• More concise: Reduced from ~140 lines to ~130 lines while improving clarity
• Transparent: Uses GoogleTest's matcher framework with explicit comparison logic that's easy to understand
• Self-contained: Tests are easier to understand without helper function indirection

✅ All 28 tests pass successfully

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[Copilot]

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[niklas-uhl]

@copilot Can we make this more concise using a more complex matcher statement and can we get completely rid of the check_edge_range function? I like tests do be concise without too much indirection.

[Copilot]

Done in commit 74f5a41. I've:

1. Removed both check_edge_range helper functions
2. Inlined the logic directly into each test using a lambda
3. Made the matcher more concise by using std::vector(edge_range.begin(), edge_range.end()) directly in the EXPECT_THAT statement

The tests are now more self-contained and easier to read without the extra indirection.

[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

[niklas-uhl]

@copilot this if is unnecessary here

[Copilot]

Fixed in commit f31168a. Removed the unnecessary CSR check from both edgelist tests since they use UseEdgeListRepresentation() and will never have CSR representation.

[niklas-uhl]

@copilot can we turn this into a parameterized test?

[Copilot]

Done in commit d323aac. Converted to parameterized tests by generator type (GNM, RMAT, RGG2D, RGG3D, RHG, Grid2D, Grid3D). This creates 28 test cases (7 generators × 4 variations) with descriptive names like EdgeRangeTests/EdgeRangeTestFixture.iterate_edgelist_representation/GNM.

[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

[niklas-uhl]

@copilot for the CSR test, the if is always true, so you can also remove the check

[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

[Copilot]

@copilot for the CSR test, the if is always true, so you can also remove the check

This was already addressed in commit d323aac. The CSR tests now directly call BuildEdgeListFromCSR(graph.vertex_range, graph.xadj, graph.adjncy) without any if statement (lines 93 and 116).

[niklas-uhl]

@copilot use a custom matcher for the index check, like so

MATCHER_P(MatchesEdgeIndex, expected_idx, "") {
    return arg.edge_index() == expected_idx;
}

EXPECT_THAT(actual, Pointwise(MatchesEdgeIndex(), expected_indices));

[Copilot]

@copilot use a custom matcher for the index check, like so

MATCHER_P(MatchesEdgeIndex, expected_idx, "") {

...

Done in commit e00466c. Created a custom matcher HasConsecutiveEdgeIndices that checks edge indices without allocating a vector. The matcher iterates through the edge range once and validates that each iterator's edge_index() matches the expected consecutive value, with helpful error messages when indices don't match.

[niklas-uhl]

@copilot Maybe the previous version was better, since it does not hide too much of what is going on, revert that commit

[Copilot]

@copilot Maybe the previous version was better, since it does not hide too much of what is going on, revert that commit

Reverted in commit 0c143fb. The tests now use the explicit loop for edge index verification, making it clearer what's being checked.

[niklas-uhl]

@copilot No, the pointwise stuff with EdgeIndexIs as a matcher is what I want

[Copilot]

@copilot No, the pointwise stuff with EdgeIndexIs as a matcher is what I want

Implemented in commit 6229c47. Using Pointwise with a custom EdgeIndexMatches matcher that compares iterator edge indices with expected values. The matcher checks pairs of (iterator, expected_index) to verify edge indices are consecutive.

[niklas-uhl]

@copilot can we avoid collecting the iterators in a vector by adding appropriate member type defs for the edge range or the iterator?

[Copilot]

@copilot can we avoid collecting the iterators in a vector by adding appropriate member type defs for the edge range or the iterator?

Unfortunately, we can't avoid collecting the iterators without significant changes. The issue is that Pointwise expects to dereference container elements, but we want to pass the iterators themselves (not what they dereference to) for the edge index check. Adding typedefs to EdgeRange doesn't solve this fundamental mismatch - when Pointwise iterates over EdgeRange, it dereferences to get Edge values, not the iterators.

We could either:

1. Keep the current approach (collect iterators in a vector using the range constructor std::vector<EdgeRange::iterator>(edge_range.begin(), edge_range.end()))
2. Create a custom wrapper/adapter class around EdgeRange that provides iterators as values
3. Revert to the explicit loop approach

Would you prefer option 1 (most efficient) or should we go back to the explicit loop for clarity?

[niklas-uhl]

@mschimek what do you think?

[mschimek]

option 1 is fine with me, but I doubt that it is the "most efficient" variant