move test implementations to a shared internal package

internal/test/struct.go

@@ -0,0 +1,40 @@
+package test
+
+type TestStruct struct {
+	String   string
+	Int      int
+	Float    float64
+	Bool     bool
+	Data     any
+	IntSlice []int
+}
+
+func (t TestStruct) GetString() string {
+	return t.String
+}
+
+func (t TestStruct) GetInt() int {
+	return t.Int
+}
+
+func (t TestStruct) GetFloat() float64 {
+	return t.Float
+}
+
+func (t TestStruct) GetBool() bool {
+	return t.Bool
+}
+
+func (t TestStruct) GetData() any {
+	return t.Data
+}
+
+func (t TestStruct) GetIntSlice() []int {
+	return t.IntSlice
+}
+
+func (t TestStruct) Void() {}
+
+func (t TestStruct) MultipleReturnValues() (string, int) {
+	return t.String, t.Int
+}