test: DTail fork — integration test suite and fixtures

Squashed development of the integration test suite (integrationtests/) covering
DCat, DGrep, DMap (serverless + server mode), DTail follow, DServer, DTailHealth,
journal source reads, auth-key fast reconnect, interactive query reload,
client-deadline/timeout behaviour, and the single-mode read/output path.

Includes real test fixtures (dserver*.cfg, dmap_csv_multifile_*.csv.in,
test_server_*.json, *.expected golden files) and deterministic synchronization
helpers (waitContains-style barriers) replacing racy fixed-timing assertions.

Accidental debug/output dumps that earlier commits added here (captured client
output, strace logs, ad-hoc turbo_test_output/manual_output/test_output files,
throwaway debug scripts) are intentionally excluded and gitignored.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/integrationtests/dmap_csv_multifile_test.go b/integrationtests/dmap_csv_multifile_test.go
new file mode 100644
index 0000000..2b86e06
--- /dev/null
+++ b/integrationtests/dmap_csv_multifile_test.go
@@ -0,0 +1,92 @@
+package integrationtests
+
+import (
+	"context"
+	"fmt"
+	"testing"
+)
+
+// TestDMapCSVMultiFile regression-tests the bug where the CSV log-format
+// parser consumed the first line of every file as a header, silently
+// treating the second (and later) files' header rows as data rows and
+// corrupting aggregates. With two CSV files that have 2 and 3 data rows
+// respectively we must observe exactly 5 data rows — not 6.
+func TestDMapCSVMultiFile(t *testing.T) {
+	cleanupTmpFiles(t)
+	testLogger := NewTestLogger("TestDMapCSVMultiFile")
+	defer testLogger.WriteLogFile()
+	runDualModeTest(t, DualModeTest{
+		Name:           "TestDMapCSVMultiFile",
+		ServerlessTest: func(t *testing.T) { testDMapCSVMultiFileServerless(t, testLogger) },
+		ServerTest:     func(t *testing.T) { testDMapCSVMultiFileWithServer(t, testLogger) },
+	})
+}
+
+func testDMapCSVMultiFileServerless(t *testing.T, logger *TestLogger) {
+	inFileA := "dmap_csv_multifile_a.csv.in"
+	inFileB := "dmap_csv_multifile_b.csv.in"
+	csvFile := "dmap_csv_multifile_serverless.csv.tmp"
+	expectedCsvFile := "dmap_csv_multifile.csv.expected"
+	queryFile := fmt.Sprintf("%s.query", csvFile)
+	outFile := "dmap_csv_multifile_serverless.stdout.tmp"
+	cleanupFiles(t, csvFile, queryFile, outFile)
+
+	query := fmt.Sprintf("select count($line) group by * logformat csv outfile %s", csvFile)
+
+	ctxTimeout, cancel := createTestContextWithTimeout(t)
+	ctx := WithTestLogger(ctxTimeout, logger)
+	defer cancel()
+	_, err := runCommand(ctx, t, outFile,
+		"../dmap", "--query", query, "--cfg", "none", inFileA, inFileB)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if err := compareFilesContentsWithContext(ctx, t, csvFile, expectedCsvFile); err != nil {
+		t.Error(err)
+	}
+	if err := verifyQueryFile(t, queryFile, query); err != nil {
+		t.Error(err)
+	}
+}
+
+func testDMapCSVMultiFileWithServer(t *testing.T, logger *TestLogger) {
+	ctx := WithTestLogger(context.Background(), logger)
+	inFileA := "dmap_csv_multifile_a.csv.in"
+	inFileB := "dmap_csv_multifile_b.csv.in"
+	csvFile := "dmap_csv_multifile_server.csv.tmp"
+	expectedCsvFile := "dmap_csv_multifile.csv.expected"
+	queryFile := fmt.Sprintf("%s.query", csvFile)
+	outFile := "dmap_csv_multifile_server.stdout.tmp"
+	cleanupFiles(t, csvFile, queryFile, outFile)
+
+	server := NewTestServer(t)
+	if err := server.Start("error"); err != nil {
+		t.Error(err)
+		return
+	}
+
+	query := fmt.Sprintf("select count($line) group by * logformat csv outfile %s", csvFile)
+
+	args := NewCommandArgs()
+	args.Servers = []string{server.Address()}
+	args.TrustAllHosts = true
+	args.NoColor = true
+	args.Files = []string{inFileA, inFileB}
+	args.ExtraArgs = []string{"--query", query}
+
+	_, err := runCommand(server.ctx, t, outFile,
+		"../dmap", args.ToSlice()...)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if err := compareFilesContentsWithContext(ctx, t, csvFile, expectedCsvFile); err != nil {
+		t.Error(err)
+	}
+	if err := verifyQueryFile(t, queryFile, query); err != nil {
+		t.Error(err)
+	}
+}