Add CLI JSON value parsing

cli_json_test.go

@@ -0,0 +1,44 @@
+package commandkit
+
+import (
+	"errors"
+	"math"
+	"reflect"
+	"strconv"
+	"testing"
+)
+
+func TestParseCLIJSONValues(t *testing.T) {
+	for _, tc := range []struct {
+		input string
+		want  any
+	}{
+		{`{"a":[null,true,"x",-9223372036854775808,9223372036854775807,9223372036854775808,18446744073709551615],"b":{"n":1.0,"exp":1e3}}`, map[string]any{
+			"a": []any{nil, true, "x", int64(math.MinInt64), int64(math.MaxInt64), uint64(1 << 63), uint64(math.MaxUint64)},
+			"b": map[string]any{"n": float64(1), "exp": float64(1000)},
+		}},
+		{`0`, int64(0)}, {`-0`, int64(0)}, {`42.0`, float64(42)}, {`1e0`, float64(1)},
+		{`0.1`, float64(0.1)}, {`"1"`, "1"}, {`false`, false}, {`null`, nil},
+	} {
+		t.Run(tc.input, func(t *testing.T) {
+			got, err := ParseCLIJSON(tc.input)
+			if err != nil || !reflect.DeepEqual(got, tc.want) {
+				t.Fatalf("got %#v, %v; want %#v", got, err, tc.want)
+			}
+		})
+	}
+}
+
+func TestParseCLIJSONRejectsInvalidInput(t *testing.T) {
+	for _, input := range []string{"", "[", "01", `1 2`, `true false`, `{} garbage`, `-9223372036854775809`, `18446744073709551616`, `1e400`, `[-1e400]`} {
+		t.Run(input, func(t *testing.T) {
+			if _, err := ParseCLIJSON(input); err == nil {
+				t.Fatalf("accepted %q", input)
+			}
+		})
+	}
+	_, err := ParseCLIJSON(`18446744073709551616`)
+	if !errors.Is(err, strconv.ErrRange) {
+		t.Fatalf("range error = %v", err)
+	}
+}