Add a test for input errors

Send various malformed JSON strings into the decoder for each type,
and check we get an error each time.

value_tests/error_test.go

@@ -0,0 +1,36 @@
+package test
+
+import (
+	"github.com/json-iterator/go"
+	"github.com/stretchr/testify/require"
+	"reflect"
+	"testing"
+)
+
+func Test_errorInput(t *testing.T) {
+	for _, testCase := range unmarshalCases {
+		if testCase.obj != nil {
+			continue
+		}
+		valType := reflect.TypeOf(testCase.ptr).Elem()
+		t.Run(valType.String(), func(t *testing.T) {
+			for _, data := range []string{
+				`x`,
+				`n`,
+				`nul`,
+				`{x}`,
+				`{"x"}`,
+				`{"x": "y"x}`,
+				`{"x": "y"`,
+				`{"x": "y", "a"}`,
+				`[`,
+				`[{"x": "y"}`,
+			} {
+				ptrVal := reflect.New(valType)
+				ptr := ptrVal.Interface()
+				err := jsoniter.ConfigCompatibleWithStandardLibrary.Unmarshal([]byte(data), ptr)
+				require.Error(t, err, "on input %q", data)
+			}
+		})
+	}
+}