Add "must" functions for tersely asserting function success #2
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| // Must0 is similar to Must but for functions returning just an error, without a | ||
| // value. | ||
| func Must0(err error) func(T) { |
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This function wouldn't have to be curried since a unary function call can be passed to another function directly even when there are other parameters. However, I opted to follow the pattern of the other functions for consistency.
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Definitely took me a minute to really understand why we're returning an unary function of T. But now I get it. I kinda long for a type-safe arg spread operator. this is a reasonably un-awkward solution.
| // Must3 is similar to Must but for functions returning three values and an | ||
| // error. | ||
| func Must3[V1 any, V2 any, V3 any](value1 V1, value2 V2, value3 V3, err error) func(T) (V1, V2, V3) { |
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I had to draw the line somewhere, and I stopped at three return values (plus the error). Anything over one or maybe two non-error return values is arguably already excessive.
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Seems reasonable - though we could go-generate MustN if we had to
| // Must0 is similar to Must but for functions returning just an error, without a | ||
| // value. | ||
| func Must0(err error) func(T) { |
There was a problem hiding this comment.
Definitely took me a minute to really understand why we're returning an unary function of T. But now I get it. I kinda long for a type-safe arg spread operator. this is a reasonably un-awkward solution.
Dependencies
None.
Documentation
Inspired by test utilities such as this one in a
go-commonbranch.Description
This adds a family of four new functions:
Must0,Must,Must2, andMust3(named in the spirit of theitertypes). These functions take some number of values and an error, and return a function that when called with a*testing.Teither returns the values or fails immediately, if the error is non-nil. Currying the*testing.Targument allows functions with multiple return values to be invoked directly within theMust*call, without assigning them to intermediate values first. The_mustfunction these are based on panics, but I think failing usingFatalfcan produce nicer error messages.Versioning
Minor. Note that this contains a small breaking change since I added a method (
Fatalf) to theexpect.Tinterface. However,expectis still v0, and looking at howexpect.Tis used in our code, there shouldn't be any breakage anyway.