1 files changed, 112 insertions, 0 deletions
diff --git a/test/reflect_test.go b/test/reflect_test.go
new file mode 100644
index 0000000..10909b3
--- /dev/null
+++ b/test/reflect_test.go
@@ -0,0 +1,112 @@
+package arg
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func assertCardinality(t *testing.T, typ reflect.Type, expected cardinality) {
+	actual, err := cardinalityOf(typ)
+	assert.Equal(t, expected, actual, "expected %v to have cardinality %v but got %v", typ, expected, actual)
+	if expected == unsupported {
+		assert.Error(t, err)
+	}
+}
+
+func TestCardinalityOf(t *testing.T) {
+	var b bool
+	var i int
+	var s string
+	var f float64
+	var bs []bool
+	var is []int
+	var m map[string]int
+	var unsupported1 struct{}
+	var unsupported2 []struct{}
+	var unsupported3 map[string]struct{}
+	var unsupported4 map[struct{}]string
+
+	assertCardinality(t, reflect.TypeOf(b), zero)
+	assertCardinality(t, reflect.TypeOf(i), one)
+	assertCardinality(t, reflect.TypeOf(s), one)
+	assertCardinality(t, reflect.TypeOf(f), one)
+
+	assertCardinality(t, reflect.TypeOf(&b), zero)
+	assertCardinality(t, reflect.TypeOf(&s), one)
+	assertCardinality(t, reflect.TypeOf(&i), one)
+	assertCardinality(t, reflect.TypeOf(&f), one)
+
+	assertCardinality(t, reflect.TypeOf(bs), multiple)
+	assertCardinality(t, reflect.TypeOf(is), multiple)
+
+	assertCardinality(t, reflect.TypeOf(&bs), multiple)
+	assertCardinality(t, reflect.TypeOf(&is), multiple)
+
+	assertCardinality(t, reflect.TypeOf(m), multiple)
+	assertCardinality(t, reflect.TypeOf(&m), multiple)
+
+	assertCardinality(t, reflect.TypeOf(unsupported1), unsupported)
+	assertCardinality(t, reflect.TypeOf(&unsupported1), unsupported)
+	assertCardinality(t, reflect.TypeOf(unsupported2), unsupported)
+	assertCardinality(t, reflect.TypeOf(&unsupported2), unsupported)
+	assertCardinality(t, reflect.TypeOf(unsupported3), unsupported)
+	assertCardinality(t, reflect.TypeOf(&unsupported3), unsupported)
+	assertCardinality(t, reflect.TypeOf(unsupported4), unsupported)
+	assertCardinality(t, reflect.TypeOf(&unsupported4), unsupported)
+}
+
+type implementsTextUnmarshaler struct{}
+
+func (*implementsTextUnmarshaler) UnmarshalText(text []byte) error {
+	return nil
+}
+
+func TestCardinalityTextUnmarshaler(t *testing.T) {
+	var x implementsTextUnmarshaler
+	var s []implementsTextUnmarshaler
+	var m []implementsTextUnmarshaler
+	assertCardinality(t, reflect.TypeOf(x), one)
+	assertCardinality(t, reflect.TypeOf(&x), one)
+	assertCardinality(t, reflect.TypeOf(s), multiple)
+	assertCardinality(t, reflect.TypeOf(&s), multiple)
+	assertCardinality(t, reflect.TypeOf(m), multiple)
+	assertCardinality(t, reflect.TypeOf(&m), multiple)
+}
+
+func TestIsExported(t *testing.T) {
+	assert.True(t, isExported("Exported"))
+	assert.False(t, isExported("notExported"))
+	assert.False(t, isExported(""))
+	assert.False(t, isExported(string([]byte{255})))
+}
+
+func TestCardinalityString(t *testing.T) {
+	assert.Equal(t, "zero", zero.String())
+	assert.Equal(t, "one", one.String())
+	assert.Equal(t, "multiple", multiple.String())
+	assert.Equal(t, "unsupported", unsupported.String())
+	assert.Equal(t, "unknown(42)", cardinality(42).String())
+}
+
+func TestIsZero(t *testing.T) {
+	var zero int
+	var notZero = 3
+	var nilSlice []int
+	var nonNilSlice = []int{1, 2, 3}
+	var nilMap map[string]string
+	var nonNilMap = map[string]string{"foo": "bar"}
+	var uncomparable = func() {}
+
+	assert.True(t, isZero(reflect.ValueOf(zero)))
+	assert.False(t, isZero(reflect.ValueOf(notZero)))
+
+	assert.True(t, isZero(reflect.ValueOf(nilSlice)))
+	assert.False(t, isZero(reflect.ValueOf(nonNilSlice)))
+
+	assert.True(t, isZero(reflect.ValueOf(nilMap)))
+	assert.False(t, isZero(reflect.ValueOf(nonNilMap)))
+
+	assert.False(t, isZero(reflect.ValueOf(uncomparable)))
+}