mem: simplify Sizeof/Alignof; testx: add ShouldPanic

mem/mem.go

@@ -11,18 +11,18 @@ const (
 	Terabyte
 )
 
-// SizeOf returns the size (in bytes) of the given type.
+// Sizeof returns the size (in bytes) of the given type.
 //
 // Not to be confused with [unsafe.Sizeof] which returns the size of a type via an expression.
-func SizeOf[T any]() uintptr {
-	return unsafe.Sizeof(ZeroValue[T]())
+func Sizeof[T any]() uintptr {
+	return unsafe.Sizeof(*(*T)(nil))
 }
 
-// AlignOf returns the alignment (in bytes) of the given type.
+// Alignof returns the alignment (in bytes) of the given type.
 //
 // Not to be confused with [unsafe.AlignOf] which returns the alignment of a type via an expression.
-func AlignOf[T any]() uintptr {
-	return unsafe.Alignof(ZeroValue[T]())
+func Alignof[T any]() uintptr {
+	return unsafe.Alignof(*(*T)(nil))
 }
 
 // ZeroValue returns the zero value of a given type.
@@ -34,7 +34,7 @@ func ZeroValue[T any]() (_ T) {
 //
 // BitCast panics if the sizes of the types differ.
 func BitCast[TOut any, TIn any](value *TIn) TOut {
-	if SizeOf[TOut]() != SizeOf[TIn]() {
+	if Sizeof[TOut]() != Sizeof[TIn]() {
 		panic("bitcast: sizes of types must match")
 	}
 	return *((*TOut)(unsafe.Pointer(value)))

testx/testx.go

@@ -7,10 +7,18 @@ func Expect(t *testing.T, cond bool, message ...any) {
 
 	if !cond {
 		if len(message) == 0 {
-			message = append(message, "assertion failed")
+			message = append(message, "expectation failed")
 		}
 
 		str := message[0].(string)
 		t.Fatalf(str, message[1:]...)
 	}
 }
+
+func ShouldPanic(t *testing.T, f func()) {
+	t.Helper()
+
+	defer func() { recover() }()
+	f()
+	t.Fatal("expected panic")
+}