feat: Add more unit tests

Author: ZPascal

cloudfoundry-operations/src/test/java/org/cloudfoundry/operations/applications/DefaultApplicationsTest.java

@@ -1401,6 +1401,57 @@ void logsTailLogCache() {
                 .verify(Duration.ofSeconds(5));
     }
 
+    @Test
+    void logsTailLogCacheMultipleEnvelopes() {
+        TailLogsRequest tailRequest =
+                TailLogsRequest.builder().sourceId("test-source-id").build();
+        requestLogsTailLogCacheMultiple(this.logCacheClient, tailRequest);
+
+        this.applications
+                .logsTail(tailRequest)
+                .take(3)
+                .map(e -> e.getLog().getType())
+                .as(StepVerifier::create)
+                .expectNext(LogType.OUT)
+                .expectNext(LogType.ERR)
+                .expectNext(LogType.OUT)
+                .expectComplete()
+                .verify(Duration.ofSeconds(5));
+    }
+
+    @Test
+    void logsTailLogCacheError() {
+        TailLogsRequest tailRequest =
+                TailLogsRequest.builder().sourceId("test-source-id").build();
+        when(this.logCacheClient.logsTail(tailRequest))
+                .thenReturn(Flux.error(new RuntimeException("log-cache unavailable")));
+
+        this.applications
+                .logsTail(tailRequest)
+                .as(StepVerifier::create)
+                .expectErrorMatches(
+                        t ->
+                                t instanceof RuntimeException
+                                        && "log-cache unavailable".equals(t.getMessage()))
+                .verify(Duration.ofSeconds(5));
+    }
+
+    @Test
+    void logsTailLogCacheOutAndErrEnvelopes() {
+        TailLogsRequest tailRequest =
+                TailLogsRequest.builder().sourceId("test-source-id").build();
+        requestLogsTailLogCacheOutAndErr(this.logCacheClient, tailRequest);
+
+        this.applications
+                .logsTail(tailRequest)
+                .take(2)
+                .as(StepVerifier::create)
+                .expectNextMatches(e -> LogType.OUT.equals(e.getLog().getType()))
+                .expectNextMatches(e -> LogType.ERR.equals(e.getLog().getType()))
+                .expectComplete()
+                .verify(Duration.ofSeconds(5));
+    }
+
     @SuppressWarnings("deprecation")
     @Test
     void logsRecentNotSetDoppler() {
@@ -5418,6 +5469,54 @@ private static void requestLogsTailLogCache(
                                         .build()));
     }
 
+    /**
+     * Three envelopes with types OUT, ERR, OUT and strictly ascending timestamps so ordering
+     * is deterministic.
+     */
+    private static void requestLogsTailLogCacheMultiple(
+            LogCacheClient logCacheClient, TailLogsRequest tailRequest) {
+        long base = System.nanoTime();
+        when(logCacheClient.logsTail(tailRequest))
+                .thenReturn(
+                        Flux.just(
+                                Envelope.builder()
+                                        .sourceId(tailRequest.getSourceId())
+                                        .timestamp(base)
+                                        .log(Log.builder().payload("msg1").type(LogType.OUT).build())
+                                        .build(),
+                                Envelope.builder()
+                                        .sourceId(tailRequest.getSourceId())
+                                        .timestamp(base + 1)
+                                        .log(Log.builder().payload("msg2").type(LogType.ERR).build())
+                                        .build(),
+                                Envelope.builder()
+                                        .sourceId(tailRequest.getSourceId())
+                                        .timestamp(base + 2)
+                                        .log(Log.builder().payload("msg3").type(LogType.OUT).build())
+                                        .build()));
+    }
+
+    /**
+     * Two envelopes – one STDOUT, one STDERR – to verify both log types are forwarded.
+     */
+    private static void requestLogsTailLogCacheOutAndErr(
+            LogCacheClient logCacheClient, TailLogsRequest tailRequest) {
+        long base = System.nanoTime();
+        when(logCacheClient.logsTail(tailRequest))
+                .thenReturn(
+                        Flux.just(
+                                Envelope.builder()
+                                        .sourceId(tailRequest.getSourceId())
+                                        .timestamp(base)
+                                        .log(Log.builder().payload("stdout").type(LogType.OUT).build())
+                                        .build(),
+                                Envelope.builder()
+                                        .sourceId(tailRequest.getSourceId())
+                                        .timestamp(base + 1)
+                                        .log(Log.builder().payload("stderr").type(LogType.ERR).build())
+                                        .build()));
+    }
+
     private static void requestLogsStream(DopplerClient dopplerClient, String applicationId) {
         when(dopplerClient.stream(StreamRequest.builder().applicationId(applicationId).build()))
                 .thenReturn(