zjeremiah / trial

A simple golang testing support package making Table Driven Tests easier to write.

Trial - Prove the Innocence of your code

Go testing framework to make tests easier to create, maintain and debug.

See wiki for tips and guides

Examples	Compare Functions	Helper Functions

Philosophy

• Table Driven Tests
• Descriptive
  • tests should describe the expected behavior of a function
  • case needs unique description
  • easy to read and change
• Fast - the test suite should run in under 5 minutes
• Independent
  • Each case should be fully isolated
  • doesn't depend on previous cases running
  • order of cases shouldn't matter
• Repeatable: non-flaky, runs regardless of the time of year
• Test for observable behavior

Features

• function verification.
  • Check results for exact matches including private values (default behavior)
  • Check results for values contained in others (see Contains function)
  • Allows for custom compare functions
• Catch and test for panics
  • each test is self isolated so a panic won't stop other cases from running
  • check for expected panic cases with ShouldPanic
• Test error cases
  • Check that a function returns an error: ShouldErr
  • Check that an error strings contains expected string: ExpectedErr
  • Check that an error is of expected type: ExpectedErr: ErrType(err)
• Fail tests that take too long to complete
  • trial.New(fn,cases).Timeout(time.Second)

Getting Starting

go get github.com/hydronica/trial

Each test has 3 parts to it. A function to test against, a set of test cases to validate with and trial that sets up the table driven tests

Test Function

testFunc[In any, Out any] func(in In) (result Out, err error)

a generic function that has a single input and returns a result and an error. Wrap your function to test more complex functions or methods.

Example

  fn := func(i int) (string, error) {
    return strconv.ItoA(i), nil 
  }

Cases

a collection (map) of test cases that have a unique title and defined input to be passed to the test function. The expected behavior is described by providing an output, setting an ExpectedErr or saying it ShouldErr. ShouldPanic can be used to test when function panic condition.

type Case[In any, Out any] struct {
	Input    In
	Expected Out


	ShouldErr   bool  // is an error expected
	ExpectedErr error // the error that was expected (nil is no error expected)
	ShouldPanic bool  // is a panic expected
}

Each

• Input generic - a convenience structure to handle input more dynamically
• Expected generic - the expected output of the method being tested.
  • This is compared with the result from the TestFunc
• ShouldErr bool - indicates the function should return an error
• ExpectedErr error - verifies the function error string matches the result
  • uses strings.Contains to check
  • also implies that the method should error so setting ShouldErr to true is not required
  • use ErrType to test that the error is the same type as expected.
• ShouldPanic bool - indicates the method should panic

Trial Setup

Run the test cases either within a single test function or as subtests. The input and output values must match between the test function and cases.

trial.New(fn,cases).Test(t)
// or 
trial.New(fn,cases).SubTest(t)

By default trial uses a strict matching values and uses cmp.Equal to compare values. Compare Functions can be customized to ignore certain fields or are contained withing maps, slices or strings. See Compare Functions for more details. A timeout can be added onto the trial builder with .Timeout(time.Second)

Getting Started Template

fn := func(in any) (any, error) {
    // TODO: setup test case, call routine and return result
    return nil, nil
}
cases := trail.Cases{
    "default": {
        Input:    123,
        Expected: 1,
    },
}
trial.New(fn,cases).Test(t)

For more examples see the wiki

Compare Functions

used to compare two values to determine equality and displayed a detailed string describing any differences.

func(actual, expected any) (equal bool, differences string)

override the default

trial.New(fn, cases).Comparer(myComparer).Test(t)

Equal

The default comparer used, it is a wrapping for cmp.Equal with the AllowUnexported option set for all structs. This causes all fields (public and private) in a struct to be compared. (see https://github.com/google/go-cmp)

EqualOpt

Customize the use of cmp.Equal with the following supported options:

• AllowAllUnexported - [default: Equal] compare all unexported (private) variables within a struct. This is useful when testing a struct inside its own package.
• IgnoreAllUnexported - ignore all unexported (private) variables within a struct. This is useful when dealing with a struct outside the project.
• IgnoreFields(fields ...string) - define a list of variables to exclude for the comparer, the field name are case sensitize and can be dot-delimited ("Field", "Parent.child")
• EquateEmpty- [default: Equal] a nil map or slice is equal to an empty one (len is zero)
• IgnoreTypes(values ...interface{}) - ignore all types of the values passed in. Ex: IgnoreTypes(int64(0), float32(0.0)) ignore int64 and float32
• ApproxTime(d time.Duration) - approximates time values to to the nearest duration.

Contains ⊇

Checks if the expected value is contained in the actual value. The symbol ⊇ is used to donate a subset. ∈ is used to show that a value exists in a slice. Contains checks the following relationships

• string ⊇ string
  • is the expected string contained in the actual string (strings.Contains)
• string ⊇ []string
  • are the expected substrings contained in the actual string
• []interface{} ⊇ interface{}
  • is the expected value found in the slice or array
• []interface{} ⊇ []interface{}
  • is the expected slice a subset of the actual slice. all values in expected exist and are contained in actual.
• map[key]interface{} ⊇ map[key]interface{}
  • is the expected map a subset of the actual map. all keys in expected are in actual and all values under that key are contained in actual