st

A Tiny Test Framework for Go

A tiny test framework for making short, useful assertions in your Go tests.

Assert(t, have, want) and Refute(t, have, want) abort a test immediately with t.Fatal.

Expect(t, have, want) and Reject(t, have, want) allow a test to continue, reporting failure at the end with t.Error.

They print nice error messages, preserving the order of have (actual result) before want (expected result) to minimize confusion.

Usage

Examples of passing tests from readme_test.go:

func TestExample(t *testing.T) {
	st.Expect(t, "a", "a")
	st.Reject(t, 42, int64(42))

	st.Assert(t, "b", "b")
	st.Refute(t, 99, int64(99))
}

func TestTableExample(t *testing.T) {
	examples := []struct{ a, b string }{
		{"first", "first"},
		{"second", "second"},
	}

	// Pass the index to improve the error message for table-based tests.
	for i, ex := range examples {
		st.Expect(t, ex, ex, i)
		st.Reject(t, ex, &ex, i)
	}

	// Cannot pass index into Assert or Refute, they fail fast.
	for _, ex := range examples {
		st.Assert(t, ex, ex)
		st.Refute(t, ex, &ex)
	}
}

=== RUN TestExample
--- PASS: TestExample (0.00 seconds)
=== RUN TestTableExample
--- PASS: TestTableExample (0.00 seconds)
PASS
ok  	github.com/nbio/st	0.010s

Failing tests produce nice output:

func TestFailedExpectationMessages(t *testing.T) {
	st.Expect(t, 1, 2)
	st.Reject(t, "same", "same")
	var typedNil *string
	st.Expect(t, typedNil, nil) // in Go, a typed nil != nil
}

func TestFailedAssertMessage(t *testing.T) {
	type chicken struct{}
	type egg struct{}
	st.Assert(t, egg{}, chicken{})
}

func TestFailedRefuteMessage(t *testing.T) {
	st.Reject(t, 42, 7*6)
}

func TestFailedTableMessages(t *testing.T) {
	table := []struct{ val int }{
		{0}, {1}, {2},
	}
	// Continues if expectation fails
	for i, example := range table {
		st.Expect(t, example.val, 1, i)
	}
	// Stops when first assertion fails
	for _, example := range table {
		st.Assert(t, example.val, 1)
	}
}

func TestDeeperEquality(t *testing.T) {
	type testStr string
	slice1 := []interface{}{"A", 1, []byte("steak sauce")}
	slice2 := []interface{}{"R", 2, 'd', int64(2)}
	map1 := map[string]string{"clever": "crafty", "modest": "prim"}
	map2 := map[string]string{"silk": "scarf", "wool": "sweater"}
	str1 := "same"
	str2 := testStr("same")

	st.Expect(t, slice1, slice2)
	st.Reject(t, slice1, slice1)
	st.Expect(t, map1, map2)
	st.Reject(t, map1, map1)
	st.Expect(t, str1, str2)
	st.Reject(t, str1, str1)
}

--- FAIL: TestFailedExpectationMessages (0.00 seconds)
	readme_test.go:38: Tests purposely fail to demonstrate output
	st.go:41:
		readme_test.go:39: should be ==
		 	have: (int) 2
			want: (int) 1
	st.go:50:
		readme_test.go:40: should be !=
		 	have: (string) same
			and : (string) same
	st.go:41:
		readme_test.go:42: should be ==
		 	have: (<nil>) <nil>
			want: (*string) <nil>
--- FAIL: TestFailedAssertMessage (0.00 seconds)
	st.go:59:
		readme_test.go:49: should be ==
		 	have: (readme.chicken) {}
			want: (readme.egg) {}
--- FAIL: TestFailedRefuteMessage (0.00 seconds)
	st.go:50:
		readme_test.go:54: should be !=
		 	have: (int) 42
			and : (int) 42
--- FAIL: TestFailedTableMessages (0.00 seconds)
	st.go:41:
		readme_test.go:64: should be ==
		0. 	have: (int) 1
			want: (int) 0
	st.go:41:
		readme_test.go:64: should be ==
		2. 	have: (int) 1
			want: (int) 2
	st.go:59:
		readme_test.go:68: should be ==
		 	have: (int) 1
			want: (int) 0
--- FAIL: TestDeeperEquality (0.00 seconds)
	st.go:41:
		readme_test.go:83: should be ==
		 	have: ([]interface {}) [R 2 100 2]
			want: ([]interface {}) [A 1 [115 116 101 97 107 32 115 97 117 99 101]]
	st.go:50:
		readme_test.go:84: should be !=
		 	have: ([]interface {}) [A 1 [115 116 101 97 107 32 115 97 117 99 101]]
			and : ([]interface {}) [A 1 [115 116 101 97 107 32 115 97 117 99 101]]
	st.go:41:
		readme_test.go:85: should be ==
		 	have: (map[string]string) map[silk:scarf wool:sweater]
			want: (map[string]string) map[clever:crafty modest:prim]
	st.go:50:
		readme_test.go:86: should be !=
		 	have: (map[string]string) map[clever:crafty modest:prim]
			and : (map[string]string) map[clever:crafty modest:prim]
	st.go:41:
		readme_test.go:87: should be ==
		 	have: (readme.testStr) same
			want: (string) same
	st.go:50:
		readme_test.go:88: should be !=
		 	have: (string) same
			and : (string) same
FAIL
exit status 1
FAIL	github.com/nbio/st/readme	0.012s

See package st documentation for more detail.