feat: create new pair-to-have-been-called-assertions rule
#1848
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nicolasgillot
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G-Rath
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pair-to-have-been-called-assertions rule
G-Rath
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Nov 16, 2025
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G-Rath
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looks like a good start - could you remove the contradictoryCallTimes logic and do any resulting simplifications, and review the istanbul comments as I'm pretty sure most should be coverable
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| When testing mock functions, developers often use `toHaveBeenCalledWith()`, | ||
| `toBeCalledWith()`, `toHaveBeenNthCalledWith()`, `toBeNthCalledWith()`, | ||
| `toHaveBeenLastCalledWith()`, or `toBeLastCalledWith()` to verify that a |
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| `toHaveBeenLastCalledWith()`, or `toBeLastCalledWith()` to verify that a | |
| `toHaveBeenLastCalledWith()`, and `toBeLastCalledWith()` to verify that a |
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| ## Examples | ||
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| ### Incorrect |
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| ### Incorrect | |
| Examples of **incorrect** code for this rule: |
| expect(mockFn).toBeLastCalledWith('last'); | ||
| ``` | ||
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| ### Correct |
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| ### Correct | |
| Examples of **correct** code with this rule: |
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| ## Additional Checks | ||
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| ### Contradictory Assertions |
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At this point I think this is out of scope for this rule - can we remove it for now?
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| However, it's generally recommended to keep this rule enabled as it helps catch | ||
| bugs where functions are called more times than expected, leading to more robust | ||
| and reliable tests. |
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I don't think this is particularly useful to have in this section, especially as this a rule that is enabled by default
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| However, it's generally recommended to keep this rule enabled as it helps catch | |
| bugs where functions are called more times than expected, leading to more robust | |
| and reliable tests. |
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Summary
This PR introduces a new ESLint rule
pair-to-have-been-called-assertionsthat enforces usingtoHaveBeenCalledTimes()ortoBeCalledTimes()whenever using matchers liketoHaveBeenCalledWith(),toBeCalledWith(),toHaveBeenNthCalledWith(),toBeNthCalledWith(),toHaveBeenLastCalledWith(), ortoBeLastCalledWith().Why?
When testing mock functions, developers often use
toHaveBeenCalledWith()to verify that a function was called with specific arguments. However, without also checking the call count, the test can pass even if the mock was called more times than expected, potentially masking bugs.What does this rule do?
toHaveBeenCalledWith()(and similar matchers) withtoHaveBeenCalledTimes()toHaveBeenCalledTimes(1)assertiontoHaveBeenCalledTimes(0)withtoHaveBeenCalledWith())toHaveBeenCalledWith,toBeCalledWith,toHaveBeenNthCalledWith,toBeNthCalledWith,toHaveBeenLastCalledWith,toBeLastCalledWithExamples
❌ Incorrect:
✅ Correct:
Resolves #1820