feat(cli): add --dry-run to convert, merge and split (#41)

Co-authored-by: SG Command <sgcommand@warky.dev>

cmd/relspec/dry_run_test.go

@@ -0,0 +1,158 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/spf13/cobra"
+)
+
+func newDryRunCmd() (*cobra.Command, *bytes.Buffer) {
+	var buf bytes.Buffer
+	cmd := &cobra.Command{}
+	cmd.SetOut(&buf)
+	return cmd, &buf
+}
+
+func TestRunConvert_DryRunWritesNothing(t *testing.T) {
+	defer func(a, b, c, d string, e bool) {
+		convertSourceType, convertSourcePath, convertTargetType, convertTargetPath, convertDryRun = a, b, c, d, e
+	}(convertSourceType, convertSourcePath, convertTargetType, convertTargetPath, convertDryRun)
+
+	dir := t.TempDir()
+	in := filepath.Join(dir, "in.json")
+	out := filepath.Join(dir, "out.json")
+	writeTestJSON(t, in, []string{"users", "posts"})
+
+	convertSourceType, convertSourcePath = "json", in
+	convertTargetType, convertTargetPath = "json", out
+	convertDryRun = true
+
+	cmd, buf := newDryRunCmd()
+	if err := runConvert(cmd, nil); err != nil {
+		t.Fatalf("dry run: %v", err)
+	}
+	if _, err := os.Stat(out); !os.IsNotExist(err) {
+		t.Fatal("dry run must not create the output file")
+	}
+	for _, want := range []string{"dry run", "users", "posts", out} {
+		if !strings.Contains(buf.String(), want) {
+			t.Errorf("plan missing %q:\n%s", want, buf.String())
+		}
+	}
+
+	// Normal behavior is unchanged.
+	convertDryRun = false
+	if err := runConvert(cmd, nil); err != nil {
+		t.Fatalf("real run: %v", err)
+	}
+	if _, err := os.Stat(out); err != nil {
+		t.Fatalf("real run should write output: %v", err)
+	}
+}
+
+func TestRunConvert_DryRunValidatesTarget(t *testing.T) {
+	defer func(a, b, c, d string, e bool) {
+		convertSourceType, convertSourcePath, convertTargetType, convertTargetPath, convertDryRun = a, b, c, d, e
+	}(convertSourceType, convertSourcePath, convertTargetType, convertTargetPath, convertDryRun)
+
+	dir := t.TempDir()
+	in := filepath.Join(dir, "in.json")
+	out := filepath.Join(dir, "models")
+	writeTestJSON(t, in, []string{"users"})
+
+	convertSourceType, convertSourcePath = "json", in
+	convertDryRun = true
+
+	// gorm without --package must fail validation, as a real run would.
+	convertTargetType, convertTargetPath = "gorm", out
+	cmd, _ := newDryRunCmd()
+	err := runConvert(cmd, nil)
+	if err == nil || !strings.Contains(err.Error(), "package name is required") {
+		t.Fatalf("expected package validation error, got %v", err)
+	}
+
+	convertTargetType = "nope"
+	err = runConvert(cmd, nil)
+	if err == nil || !strings.Contains(err.Error(), "unsupported target format") {
+		t.Fatalf("expected unsupported format error, got %v", err)
+	}
+	if _, statErr := os.Stat(out); !os.IsNotExist(statErr) {
+		t.Fatal("dry run must not create the output path")
+	}
+}
+
+func TestRunSplit_DryRunWritesNothing(t *testing.T) {
+	defer func(a, b, c, d, e string, f bool) {
+		splitSourceType, splitSourcePath, splitTargetType, splitTargetPath, splitTables, splitDryRun = a, b, c, d, e, f
+	}(splitSourceType, splitSourcePath, splitTargetType, splitTargetPath, splitTables, splitDryRun)
+
+	dir := t.TempDir()
+	in := filepath.Join(dir, "in.json")
+	out := filepath.Join(dir, "subset.json")
+	writeTestJSON(t, in, []string{"users", "posts", "comments"})
+
+	splitSourceType, splitSourcePath = "json", in
+	splitTargetType, splitTargetPath = "json", out
+	splitTables = "users,posts"
+	splitDryRun = true
+
+	cmd, buf := newDryRunCmd()
+	if err := runSplit(cmd, nil); err != nil {
+		t.Fatalf("dry run: %v", err)
+	}
+	if _, err := os.Stat(out); !os.IsNotExist(err) {
+		t.Fatal("dry run must not create the output file")
+	}
+	got := buf.String()
+	if !strings.Contains(got, "2 table(s)") || strings.Contains(got, "comments") {
+		t.Errorf("plan should show only the 2 selected tables:\n%s", got)
+	}
+
+	// A selection that matches nothing fails validation in dry-run too.
+	splitTables = "does_not_exist"
+	if err := runSplit(cmd, nil); err == nil {
+		t.Fatal("expected error for empty selection")
+	}
+}
+
+func TestRunMerge_DryRunWritesNothing(t *testing.T) {
+	saved := saveMergeState()
+	defer restoreMergeState(saved)
+	defer func(v bool) { mergeDryRun = v }(mergeDryRun)
+
+	dir := t.TempDir()
+	target := filepath.Join(dir, "target.json")
+	source := filepath.Join(dir, "source.json")
+	out := filepath.Join(dir, "merged.json")
+	writeTestJSON(t, target, []string{"users"})
+	writeTestJSON(t, source, []string{"posts"})
+
+	mergeTargetType, mergeTargetPath, mergeTargetConn = "json", target, ""
+	mergeSourceType, mergeSourcePath, mergeSourceConn = "json", source, ""
+	mergeFromList = nil
+	mergeOutputType, mergeOutputPath, mergeOutputConn = "json", out, ""
+	mergeSkipTables, mergeReportPath = "", ""
+	mergeDryRun = true
+
+	cmd, buf := newDryRunCmd()
+	if err := runMerge(cmd, nil); err != nil {
+		t.Fatalf("dry run: %v", err)
+	}
+	if _, err := os.Stat(out); !os.IsNotExist(err) {
+		t.Fatal("dry run must not create the output file")
+	}
+	for _, want := range []string{"dry run", "users", "posts", out} {
+		if !strings.Contains(buf.String(), want) {
+			t.Errorf("plan missing %q:\n%s", want, buf.String())
+		}
+	}
+
+	mergeOutputType = "nope"
+	if err := runMerge(cmd, nil); err == nil || !strings.Contains(err.Error(), "unsupported format") {
+		t.Fatalf("expected unsupported output format error, got %v", err)
+	}
+}