field: add tests for fields, WIP

field.go

@@ -15,7 +15,8 @@ func (f *Field) Tag(key string) string {
 	return f.field.Tag.Get(key)
 }
 
-// Value returns the underlying value of of the field.
+// Value returns the underlying value of of the field. It panics if the field
+// is not exported.
 func (f *Field) Value() interface{} {
 	return f.value.Interface()
 }
@@ -24,3 +25,8 @@ func (f *Field) Value() interface{} {
 func (f *Field) IsEmbedded() bool {
 	return f.field.Anonymous
 }
+
+// IsExported returns true if the given field is exported.
+func (f *Field) IsExported() bool {
+	return f.field.PkgPath == ""
+}

field_test.go

@@ -0,0 +1,49 @@
+package structure
+
+import "testing"
+
+// A test struct that defines all cases
+type Foo struct {
+	A    string
+	B    int    `structure:"y"`
+	C    bool   `json:"c"`
+	d    string // not exported
+	*Bar        // embedded
+}
+
+type Bar struct {
+	E string
+	F int
+	g []string
+}
+
+func newStruct() *Struct {
+	b := &Bar{
+		E: "example",
+		F: 2,
+		g: []string{"zeynep", "fatih"},
+	}
+
+	f := &Foo{
+		A: "gopher",
+		B: 1,
+		C: true,
+		d: "small",
+	}
+	f.Bar = b
+
+	return New(f)
+}
+
+func TestField(t *testing.T) {
+	s := newStruct()
+
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Error("Retrieveing a non existing field from the struct should panic")
+		}
+	}()
+
+	_ = s.Field("no-field")
+}