feat: add Equal and NotEqual.

Author: ghosind

assertion.go

@@ -0,0 +1,26 @@
+package assert
+
+import "testing"
+
+type Assertion struct {
+	t *testing.T
+}
+
+// New returns an assertion instance for verifying invariants.
+func New(t *testing.T) *Assertion {
+	a := new(Assertion)
+
+	a.t = t
+
+	return a
+}
+
+// Equal tests equality between actual and expect parameters.
+func (a *Assertion) Equal(actual, expect any, message ...string) error {
+	return Equal(a.t, actual, expect, message...)
+}
+
+// NotEqual tests inequality between actual and expected parameters.
+func (a *Assertion) NotEqual(actual, expect any, message ...string) error {
+	return NotEqual(a.t, actual, expect, message...)
+}

equal.go

@@ -0,0 +1,32 @@
+package assert
+
+import (
+	"reflect"
+	"testing"
+)
+
+// Equal tests equality between actual and expect parameters.
+func Equal(t *testing.T, actual, expect any, message ...string) error {
+	if reflect.DeepEqual(actual, expect) {
+		return nil
+	}
+
+	err := newAssertionError("==", actual, expect, message...)
+
+	t.Error(err)
+
+	return err
+}
+
+// NotEqual tests inequality between actual and expected parameters.
+func NotEqual(t *testing.T, actual, expect any, message ...string) error {
+	if !reflect.DeepEqual(actual, expect) {
+		return nil
+	}
+
+	err := newAssertionError("!=", actual, expect, message...)
+
+	t.Error(err)
+
+	return err
+}

equal_test.go

@@ -0,0 +1,47 @@
+package assert
+
+import "testing"
+
+type testStruct struct {
+	v int
+}
+
+func TestEqualAndNotEqual(t *testing.T) {
+	mockT := new(testing.T)
+	assertion := New(mockT)
+
+	testEqualAndNotEqual(t, assertion, 1, 1, true)
+	testEqualAndNotEqual(t, assertion, 1, 2, false)
+	testEqualAndNotEqual(t, assertion, 1, 1.0, false)
+	testEqualAndNotEqual(t, assertion, 1, "1", false)
+	testEqualAndNotEqual(t, assertion, 1, '1', false)
+	testEqualAndNotEqual(t, assertion, 1, []int{1}, false)
+	testEqualAndNotEqual(t, assertion, []int{1}, []int{1}, true)
+
+	obj1 := testStruct{v: 1}
+	obj2 := testStruct{v: 1}
+
+	testEqualAndNotEqual(t, assertion, obj1, obj2, true)
+	testEqualAndNotEqual(t, assertion, obj1, &obj2, false)
+	testEqualAndNotEqual(t, assertion, &obj1, &obj2, true)
+
+	obj2.v = 2
+	testEqualAndNotEqual(t, assertion, obj1, obj2, false)
+	testEqualAndNotEqual(t, assertion, &obj1, &obj2, false)
+}
+
+func testEqualAndNotEqual(t *testing.T, assertion *Assertion, v1, v2 any, isEqual bool) {
+	err := assertion.Equal(v1, v2)
+	if isEqual && err != nil {
+		t.Errorf("Equal(%v, %v) = %v, want = nil", v1, v2, err)
+	} else if !isEqual && err == nil {
+		t.Errorf("Equal(%v, %v) = nil, want = error", v1, v2)
+	}
+
+	err = assertion.NotEqual(v1, v2)
+	if isEqual && err == nil {
+		t.Errorf("NotEqual(%v, %v) = nil, want = error", v1, v2)
+	} else if !isEqual && err != nil {
+		t.Errorf("NotEqual(%v, %v) = %v, want = nil", v1, v2, err)
+	}
+}

error.go

@@ -0,0 +1,33 @@
+package assert
+
+import "fmt"
+
+// AssertionError indicates the failure of an assertion.
+type AssertionError struct {
+	message  *string
+	actual   any
+	expect   any
+	operator string
+}
+
+func newAssertionError(operator string, actual, expect any, message ...string) AssertionError {
+	err := AssertionError{
+		actual:   actual,
+		expect:   expect,
+		operator: operator,
+	}
+
+	if len(message) > 0 {
+		err.message = &message[0]
+	}
+
+	return err
+}
+
+func (err AssertionError) Error() string {
+	if err.message != nil {
+		return *err.message
+	}
+
+	return fmt.Sprintf("%v %s %v", err.actual, err.operator, err.expect)
+}