Expect Package

Package for testing Gno packages and realms using function chaining and expressive semantics.

Asserting Values

Use Value() to check that a value meets expectations. Chain Not() to negate an assertion, and use AsInt(), AsString(), AsBoolean() (and similar) to narrow to type-specific assertions.

 1package expect_test
 2
 3import (
 4	"errors"
 5	"testing"
 6
 7	"gno.land/p/g17khqpukees4237dtn3astzapmp462vjhsz6st4/expect"
 8)
 9
10func TestReadmeValue(t *testing.T) {
11	// Assert integer value
12	score := 42
13	expect.Value(t, score).ToEqual(42)
14	expect.Value(t, score).Not().ToEqual(0)
15	expect.Value(t, score).AsInt().ToBeLowerThan(100)
16
17	// Assert string value
18	name := "Alice"
19	expect.Value(t, name).AsString().ToEqual("Alice")
20	expect.Value(t, name).AsString().ToHaveLength(5)
21
22	// Assert boolean value
23	expect.Value(t, true).AsBoolean().ToBeTruthy()
24
25	// Assert pointer value
26	var v any
27	expect.Value(t, v).ToBeNil()
28
29	// Assert error value
30	err := errors.New("foo bar")
31	expect.Value(t, err).ToEqual(err)
32	expect.Value(t, err).ToContainErrorString("foo")
33}

Asserting Functions

Use Func() to check that a function returns an error, panics, or returns an expected value. Chain .ToFail(), .ToPanic(), or .ToReturn() and then assert the message or value.

Package supports four type of functions:

• func()
• func() any
• func() error
• func() (any, error)

 1package expect_test
 2
 3import (
 4	"errors"
 5	"testing"
 6
 7	"gno.land/p/g17khqpukees4237dtn3astzapmp462vjhsz6st4/expect"
 8)
 9
10func TestReadmeFunc(t *testing.T) {
11	foo := func() int {
12		return 42
13	}
14
15	fooPanic := func() {
16		panic("boom!")
17	}
18
19	err := errors.New("boom!")
20	fooError := func(err error) error {
21		return err
22	}
23
24	// Assert that "fooError" function returns an error
25	expect.Func(t, func() error {
26		return fooError(err)
27	}).ToFail().WithError(err)
28
29	// Assert that "fooPanic" function panics with a message
30	expect.Func(t, func() {
31		fooPanic()
32	}).ToPanic().WithMessage("boom!")
33
34	// Assert that "foo" function returns 42
35	expect.Func(t, func() any {
36		return foo()
37	}).ToReturn(42)
38}