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, 26 insertions, 1 deletions

diff --git a/integrationtests/fileutils.go b/integrationtests/fileutils.go
index a1e1051..064a08a 100644
--- a/integrationtests/fileutils.go
+++ b/integrationtests/fileutils.go
@@ -2,6 +2,7 @@ package integrationtests
 
 import (
 	"bufio"
+	"context"
 	"crypto/sha256"
 	"encoding/base64"
 	"fmt"
@@ -81,7 +82,7 @@ func compareFiles(t *testing.T, fileA, fileB string) error {
 		if bytes, err := exec.Command("diff", "-u", fileA, fileB).Output(); err != nil {
 			sb.Write(bytes)
 		}
-		return fmt.Errorf(sb.String())
+		return fmt.Errorf("%s", sb.String())
 	}
 
 	return nil
@@ -115,3 +116,27 @@ func shaOfFile(t *testing.T, file string) string {
 	t.Log("SHA", file, sha)
 	return sha
 }
+
+// compareFilesWithContext is a context-aware version of compareFiles that logs comparisons
+func compareFilesWithContext(ctx context.Context, t *testing.T, fileA, fileB string) error {
+	if logger := GetTestLogger(ctx); logger != nil {
+		logger.LogFileComparison(fileA, fileB, "exact (SHA256)")
+	}
+	return compareFiles(t, fileA, fileB)
+}
+
+// compareFilesContentsWithContext is a context-aware version of compareFilesContents that logs comparisons
+func compareFilesContentsWithContext(ctx context.Context, t *testing.T, fileA, fileB string) error {
+	if logger := GetTestLogger(ctx); logger != nil {
+		logger.LogFileComparison(fileA, fileB, "contents (order-independent)")
+	}
+	return compareFilesContents(t, fileA, fileB)
+}
+
+// fileContainsStrWithContext is a context-aware version of fileContainsStr that logs comparisons
+func fileContainsStrWithContext(ctx context.Context, t *testing.T, file, str string) error {
+	if logger := GetTestLogger(ctx); logger != nil {
+		logger.LogFileComparison(file, fmt.Sprintf("string '%s'", str), "contains check")
+	}
+	return fileContainsStr(t, file, str)
+}