Add first assert tests

Author: tygern

internal/assert/assert.go

@@ -2,8 +2,10 @@ package assert
 
 import (
 	"cmp"
+	"context"
 	"strings"
 	"testing"
+	"time"
 )
 
 func Equal[V comparable](t testing.TB, expected, actual V) {
@@ -42,3 +44,48 @@ func ContainsSubstring(t testing.TB, subject, substring string) {
 expected '%v' to contain '%v'`, subject, substring)
 	}
 }
+
+type PanicConfig struct {
+	Timeout time.Duration
+}
+
+type PanicOption func(*PanicConfig)
+
+func WithTimeout(timeout time.Duration) PanicOption {
+	return func(c *PanicConfig) {
+		c.Timeout = timeout
+	}
+}
+
+func NewPanicConfig(options ...PanicOption) *PanicConfig {
+	cfg := &PanicConfig{Timeout: 100 * time.Millisecond}
+	for _, opt := range options {
+		opt(cfg)
+	}
+	return cfg
+}
+
+func Panics(t testing.TB, fn func(), options ...PanicOption) any {
+	t.Helper()
+	recovered := make(chan any)
+	config := NewPanicConfig(options...)
+	ctx, cancel := context.WithTimeout(t.Context(), config.Timeout)
+	defer cancel()
+
+	// Run in a goroutine to catch any rumtime.Goexit calls
+	go func() {
+		defer func() {
+			recovered <- recover()
+		}()
+		fn()
+		t.Fatal("Expected function to panic")
+	}()
+
+	select {
+	case r := <-recovered:
+		return r
+	case <-ctx.Done():
+		t.Fatalf("Timeout (limit %v) waiting for panic", config.Timeout)
+		return nil
+	}
+}

internal/assert/assert_test.go

@@ -0,0 +1,38 @@
+package assert_test
+
+import (
+	"testing"
+
+	"github.com/initialcapacity/pi/internal/assert"
+)
+
+func assertPasses(t *testing.T, assertion func(testing.TB)) {
+	subjectTest := new(testing.T)
+
+	assertion(subjectTest)
+
+	if subjectTest.Failed() {
+		t.Error("Expected assertion to pass, but it failed")
+	}
+}
+
+func assertFails(t *testing.T, assertion func(testing.TB)) {
+	subjectTest := new(testing.T)
+
+	assert.Panics(t, func() {
+		assertion(subjectTest)
+	})
+
+	if !subjectTest.Failed() {
+		t.Error("Expected assertion to fail, but it passed")
+	}
+}
+
+func TestEquals(t *testing.T) {
+	assertPasses(t, func(tb testing.TB) {
+		assert.Equal(tb, 3, 3)
+	})
+	assertFails(t, func(tb testing.TB) {
+		assert.Equal(tb, 3, 4)
+	})
+}