UT: orderred file merge

yokofly · yokofly · commit a146377d5d42 · 2025-08-14T02:19:41.000-07:00
(now we follow strict order by file name)
usage: --src-stream='folder/*'

cd cmd/sling
cp ../../sling .
SLING_BIN=./sling go test -v -run TestOrderedFileMergeStdout
diff --git a/cmd/sling/sling_order_test.go b/cmd/sling/sling_order_test.go
@@ -0,0 +1,82 @@
+package main_test
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/flarco/g"
+	"github.com/flarco/g/process"
+)
+
+// TestOrderedFileMergeStdout verifies that when streaming from a folder of CSVs
+// using a wildcard, rows are emitted in strict filename order.
+func TestOrderedFileMergeStdout(t *testing.T) {
+	bin := os.Getenv("SLING_BIN")
+	if bin == "" {
+		t.Fatalf("SLING_BIN environment variable is not set")
+		return
+	}
+
+	// Prepare temp folder with 50 CSV files named tablename_YYYYMMDD.csv
+	dir, err := os.MkdirTemp("", "sling_order_*")
+	if err != nil {
+		t.Fatalf("failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(dir)
+
+	// Create files tablename_20240101.csv .. tablename_20240150.csv
+	for i := 1; i <= 50; i++ {
+		fname := fmt.Sprintf("tablename_202401%02d.csv", i)
+		path := filepath.Join(dir, fname)
+		content := fmt.Sprintf("id,name\n%d,row_%02d\n", i, i)
+		if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+			t.Fatalf("failed writing %s: %v", path, err)
+		}
+	}
+
+	// Run sling to merge in order and print to stdout
+	p, err := process.NewProc("bash")
+	if !g.AssertNoError(t, err) {
+		return
+	}
+	p.Capture = true
+	p.WorkDir = "../.."
+	bin = "cmd/sling/" + bin
+	p.Print = true
+
+    cmd := strings.Join([]string{
+		"set -e",
+		"shopt -s expand_aliases",
+		fmt.Sprintf("alias sling=%s", bin),
+        fmt.Sprintf("sling run --src-stream 'file://%s' --src-options '{ format: \"csv\" }' --stdout", dir),
+	}, "\n")
+
+	err = p.Run("-lc", cmd)
+	if err != nil {
+		t.Fatalf("command failed: %v\nstdout: %s\nstderr: %s", err, p.Stdout.String(), p.Stderr.String())
+	}
+
+	// Parse stdout and ensure rows 1..50 are in order (header first)
+	lines := strings.Split(strings.TrimSpace(p.Stdout.String()), "\n")
+	if len(lines) < 51 {
+		t.Fatalf("expected at least 51 lines (1 header + 50 rows), got %d", len(lines))
+	}
+
+	// Verify header
+	if lines[0] != "id,name" {
+		t.Fatalf("unexpected header: %q", lines[0])
+	}
+
+	// Verify each subsequent line has ascending id and matching name
+	for i := 1; i <= 50; i++ {
+		expected := fmt.Sprintf("%d,row_%02d", i, i)
+		if lines[i] != expected {
+			t.Fatalf("unexpected line %d: got %q, want %q", i, lines[i], expected)
+		}
+	}
+}
+
+
