feat(cmd): add the encoder mode to the toml-test adapter

Assisted-by: DeepSeek V4.1 Flash

cmd/interpres-decode/main_test.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"errors"
 	"os"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -283,3 +284,165 @@ func TestUnknownFlagReturnsTwo(t *testing.T) {
 		t.Fatalf("Run returned %d, want 2; stderr = %q", code, stderr.String())
 	}
 }
+
+// --- encoder mode ----------------------------------------------------------
+
+func TestRunEncoderScalars(t *testing.T) {
+	in := `{
+    "s":   {"type": "string", "value": "quote \" and backslash \\"},
+    "nl":  {"type": "string", "value": "line1\nline2"},
+    "i":   {"type": "integer", "value": "-9223372036854775808"},
+    "g":   {"type": "float", "value": "1.5"},
+    "f":   {"type": "float", "value": "inf"},
+    "b":   {"type": "bool", "value": "false"},
+    "dt":  {"type": "datetime", "value": "1979-05-27T07:32:00-07:00"},
+    "ldt": {"type": "datetime-local", "value": "1979-05-27T07:32:00"},
+    "ld":  {"type": "date-local", "value": "1979-05-27"},
+    "lt":  {"type": "time-local", "value": "07:32:00.999"}
+}
+`
+	var stdout, stderr bytes.Buffer
+	code := Run([]string{"-encode"}, strings.NewReader(in), &stdout, &stderr)
+	if code != 0 {
+		t.Fatalf("Run returned %d, stderr = %q", code, stderr.String())
+	}
+	want := "b = false\n" +
+		"dt = 1979-05-27T07:32:00-07:00\n" +
+		"f = inf\n" +
+		"g = 1.5\n" +
+		"i = -9223372036854775808\n" +
+		"ld = 1979-05-27\n" +
+		"ldt = 1979-05-27T07:32:00\n" +
+		"lt = 07:32:00.999000000\n" +
+		"nl = \"line1\\nline2\"\n" +
+		"s = \"quote \\\" and backslash \\\\\"\n"
+	if stdout.String() != want {
+		t.Errorf("output mismatch:\ngot:  %q\nwant: %q", stdout.String(), want)
+	}
+}
+
+func TestRunEncoderNested(t *testing.T) {
+	in := `{
+    "tbl": {"x": {"type": "bool", "value": "true"},
+            "sub": {"y": {"type": "integer", "value": "1"}}},
+    "items": [{"n": {"type": "string", "value": "a"}},
+              {"n": {"type": "string", "value": "b"}}],
+    "list": [{"type": "integer", "value": "1"}, {"type": "string", "value": "two"}],
+    "emptyTbl": {},
+    "emptyArr": []
+}
+`
+	var stdout, stderr bytes.Buffer
+	code := Run([]string{"-encode"}, strings.NewReader(in), &stdout, &stderr)
+	if code != 0 {
+		t.Fatalf("Run returned %d, stderr = %q", code, stderr.String())
+	}
+	want := "emptyArr = []\n" +
+		"list = [1, \"two\"]\n" +
+		"\n[emptyTbl]\n" +
+		"\n[tbl]\nx = true\n" +
+		"\n[tbl.sub]\ny = 1\n" +
+		"\n[[items]]\nn = \"a\"\n" +
+		"\n[[items]]\nn = \"b\"\n"
+	if stdout.String() != want {
+		t.Errorf("output mismatch:\ngot:  %q\nwant: %q", stdout.String(), want)
+	}
+}
+
+func TestRunEncoderFloatTagDecides(t *testing.T) {
+	// A float with no fraction is described by a bare integer literal, so the
+	// tag decides the type; the output must stay a float.
+	var stdout, stderr bytes.Buffer
+	in := `{"whole": {"type": "float", "value": "1"}, "exp": {"type": "float", "value": "5e+22"}}`
+	code := Run([]string{"-encode"}, strings.NewReader(in), &stdout, &stderr)
+	if code != 0 {
+		t.Fatalf("Run returned %d, stderr = %q", code, stderr.String())
+	}
+	if want := "exp = 5e+22\nwhole = 1.0\n"; stdout.String() != want {
+		t.Errorf("output mismatch:\ngot:  %q\nwant: %q", stdout.String(), want)
+	}
+}
+
+func TestRunEncoderRejectsBadInput(t *testing.T) {
+	cases := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{"not-json", "not json", "decode JSON"},
+		{"top-level-array", `[{"type": "integer", "value": "1"}]`, "must be a JSON object"},
+		{"untagged-scalar", `{"x": 1}`, "unsupported JSON value"},
+		{"literal-mismatch", `{"x": {"type": "integer", "value": "1.5"}}`, "parsed as float64"},
+		{"offset-for-local", `{"x": {"type": "datetime-local", "value": "1979-05-27T07:32:00Z"}}`, "parsed as time.Time"},
+		{"bad-literal", `{"x": {"type": "date-local", "value": "nope"}}`, "date-local"},
+		{"smuggled-statement", `{"x": {"type": "integer", "value": "1\nx = 2"}}`, "not a single bare value"},
+	}
+	for _, c := range cases {
+		var stdout, stderr bytes.Buffer
+		code := Run([]string{"-encode"}, strings.NewReader(c.in), &stdout, &stderr)
+		if code != 2 {
+			t.Errorf("%s: Run returned %d, want 2; stderr = %q", c.name, code, stderr.String())
+			continue
+		}
+		if !strings.Contains(stderr.String(), c.want) {
+			t.Errorf("%s: stderr = %q, want it to mention %q", c.name, stderr.String(), c.want)
+		}
+		if stdout.Len() != 0 {
+			t.Errorf("%s: stdout should be empty, got %q", c.name, stdout.String())
+		}
+	}
+}
+
+func TestRunEncoderFlagConflicts(t *testing.T) {
+	var stdout, stderr bytes.Buffer
+	if code := Run([]string{"-encode", "-validate"}, strings.NewReader(""), &stdout, &stderr); code != 2 {
+		t.Errorf("Run returned %d, want 2 for the two modes together", code)
+	}
+	if !strings.Contains(stderr.String(), "cannot be combined") {
+		t.Errorf("stderr = %q, want it to explain the conflict", stderr.String())
+	}
+
+	stdout.Reset()
+	stderr.Reset()
+	if code := Run([]string{"-encode", "file.json"}, strings.NewReader(""), &stdout, &stderr); code != 2 {
+		t.Errorf("Run returned %d, want 2 for an argument", code)
+	}
+}
+
+func TestEncodeAfterDecodeRoundTrip(t *testing.T) {
+	doc := `title = "x"
+flt = 1.5
+whole = 7.0
+big = 9223372036854775807
+when = 1979-05-27T07:32:00-07:00
+day = 1979-05-27
+clock = 07:32:00.999
+list = [1, "two"]
+multi = "a\nb"
+
+[tbl]
+x = true
+
+[[items]]
+n = "a"
+`
+	var tagged, stderr bytes.Buffer
+	if code := Run(nil, strings.NewReader(doc), &tagged, &stderr); code != 0 {
+		t.Fatalf("decode returned %d, stderr = %q", code, stderr.String())
+	}
+	var out bytes.Buffer
+	if code := Run([]string{"-encode"}, bytes.NewReader(tagged.Bytes()), &out, &stderr); code != 0 {
+		t.Fatalf("encode returned %d, stderr = %q", code, stderr.String())
+	}
+	want, err := interpres.Parse([]byte(doc))
+	if err != nil {
+		t.Fatalf("parse of the original: %v", err)
+	}
+	got, err := interpres.Parse(out.Bytes())
+	if err != nil {
+		t.Fatalf("parse of the encoder output (%q): %v", out.String(), err)
+	}
+	if !reflect.DeepEqual(want, got) {
+		t.Errorf("round trip changed the document:\noriginal: %#v\nencoded:  %#v\noutput: %q", want, got, out.String())
+	}
+}