[Repo Assist] test: add coverage for LazyList.rev, concat, and split#249
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gdziadkiewicz merged 2 commits intomasterfrom Mar 15, 2026
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Add 13 tests for three LazyList functions that had no direct test coverage: rev, concat, and split. - rev: empty, singleton, list, and involution (double-rev roundtrip) - concat: empty outer/inner lists, two/three sublists, mixed empty - split: documents the actual semantics — collects first n elements in reverse order and returns elements from index n+1 onward (element at index n is dropped), which is the contract used by BankersDeque and RealTimeDeque for O(n) element removal. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Adds unit test coverage for previously untested LazyList operations in the FSharpx.Collections test suite, specifically targeting correctness of rev, concat, and the (non-obvious) semantics of split.
Changes:
- Add 4 tests for
LazyList.rev(empty/singleton/multi-element + involution roundtrip). - Add 5 tests for
LazyList.concat(empty outer/empty inner + ordered concatenation). - Add 4 tests documenting and validating
LazyList.splitbehavior (reversed left part + dropping the element at indexn).
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🤖 This PR was created by Repo Assist, an automated AI assistant.
Summary
Adds 13 unit tests for three
LazyListfunctions that previously had no direct test coverage:rev,concat, andsplit.LazyList.rev(4 tests)LazyList.concat(5 tests)LazyList.split(4 tests)Documents the actual semantics of this utility function:
split ll ncollects the firstnelements ofllin reverse order as an'T list, drops the element at indexn, and returns elements from indexn+1onward as the remainingLazyList. This is the contract relied upon byBankersDeque,RealTimeDeque, and related structures for O(n) element removal.Test Status
All tests pass. Code formatted with Fantomas before commit.