Support additional flags in FirestoreEmulatorContainer (#10067)

Fixes #10060

Author: eddumelendez

modules/gcloud/src/main/java/org/testcontainers/containers/FirestoreEmulatorContainer.java

@@ -24,6 +24,8 @@ public class FirestoreEmulatorContainer extends GenericContainer<FirestoreEmulat
 
     private static final int PORT = 8080;
 
+    private String flags;
+
     public FirestoreEmulatorContainer(String image) {
         this(DockerImageName.parse(image));
     }
@@ -34,7 +36,20 @@ public FirestoreEmulatorContainer(final DockerImageName dockerImageName) {
 
         withExposedPorts(PORT);
         setWaitStrategy(Wait.forLogMessage(".*running.*$", 1));
-        withCommand("/bin/sh", "-c", CMD);
+    }
+
+    @Override
+    protected void configure() {
+        String command = CMD;
+        if (this.flags != null && !this.flags.isEmpty()) {
+            command += " " + this.flags;
+        }
+        withCommand("/bin/sh", "-c", command);
+    }
+
+    public FirestoreEmulatorContainer withFlags(String flags) {
+        this.flags = flags;
+        return this;
     }
 
     /**

modules/gcloud/src/test/java/org/testcontainers/containers/FirestoreEmulatorContainerTest.java

@@ -53,6 +53,21 @@ public void testSimple() throws ExecutionException, InterruptedException {
 
         assertThat(querySnapshot.getDocuments().get(0).getData()).containsEntry("first", "Ada");
     }
+
     // }
 
+    @Test
+    public void testWithFlags() {
+        try (
+            FirestoreEmulatorContainer emulator = new FirestoreEmulatorContainer(
+                "gcr.io/google.com/cloudsdktool/google-cloud-cli:465.0.0-emulators"
+            )
+                .withFlags("--database-mode datastore-mode")
+        ) {
+            emulator.start();
+
+            assertThat(emulator.getContainerInfo().getConfig().getCmd())
+                .anyMatch(e -> e.contains("--database-mode datastore-mode"));
+        }
+    }
 }