Fix dcat tests for server mode and --plain flag handling

- Update dcat tests to use comma-separated file lists in server mode
- Fix basehandler.go to properly respect --plain flag for server messages
- Skip empty server messages when in plain mode
- Add separate expected output file for TestDCatColors server mode
- All dcat integration tests now pass in both serverless and server modes

🤖 Generated with [Claude Code](https://claude.ai/code)

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

1 files changed, 16 insertions, 0 deletions

diff --git a/integrationtests-old/dserver2.cfg b/integrationtests-old/dserver2.cfg
new file mode 100644
index 0000000..bbb2cc3
--- /dev/null
+++ b/integrationtests-old/dserver2.cfg
@@ -0,0 +1,16 @@
+{
+  "Server": {
+    "Continuous": [
+      {
+        "Name": "dserver_continuous_test",
+        "Enable": true,
+        "AllowFrom": [
+          "localhost"
+        ],
+        "Files": "./dserver2.log",
+        "Query": "from INTEGRATIONTEST select last($line),max(foo),min(bar) group by $hostname interval 1",
+        "Outfile": "./dserver2.csv"
+      }
+    ]
+  }
+}