Add unit tests for X-Databricks-Workspace-Id header gating

Mirrors the Go SDK's `workspace_functions_test.go` coverage:

* `AppsImplTest.testWorkspaceIdHeaderSentWhenConfigured` — a workspace-scoped
  service forwards the configured workspace ID on the
  `X-Databricks-Workspace-Id` request header.
* `AppsImplTest.testWorkspaceIdHeaderOmittedWhenUnset` — when no workspace ID
  is configured, the header is not sent (so calls to legacy single-workspace
  hosts don't pick up an empty value).
* `BudgetsImplTest.testWorkspaceIdHeaderNotSentForAccountScopedService` — an
  account-scoped service never forwards the header, even if a workspace ID is
  configured. Locks in the generator gate (`if not .Service.IsAccounts`).

Signed-off-by: Divyansh Vijayvergia <divyansh.vijayvergia@databricks.com>

Author: Divyansh-db

databricks-sdk-java/src/test/java/com/databricks/sdk/service/apps/AppsImplTest.java

@@ -41,4 +41,42 @@ public void testCreateAppIncludesNoComputeParameter() throws IOException {
                 }),
             eq(App.class));
   }
+
+  // On unified ("SPOG") hosts, workspace-scoped requests must carry an
+  // X-Databricks-Workspace-Id header so the gateway can route them to the
+  // correct workspace. When ApiClient#workspaceId() returns a value, every
+  // generated *Impl must forward it on the request; when it returns null,
+  // the header must be omitted (so calls to legacy single-workspace hosts
+  // don't pick up an empty value).
+  @Test
+  public void testWorkspaceIdHeaderSentWhenConfigured() throws IOException {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    when(apiClient.workspaceId()).thenReturn("7474644166319138");
+    when(apiClient.execute(any(), any())).thenReturn(null);
+
+    AppsService apps = new AppsImpl(apiClient);
+    apps.list(new ListAppsRequest());
+
+    verify(apiClient)
+        .execute(
+            argThat(
+                (Request req) ->
+                    "7474644166319138".equals(req.getHeaders().get("X-Databricks-Workspace-Id"))),
+            any());
+  }
+
+  @Test
+  public void testWorkspaceIdHeaderOmittedWhenUnset() throws IOException {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    when(apiClient.workspaceId()).thenReturn(null);
+    when(apiClient.execute(any(), any())).thenReturn(null);
+
+    AppsService apps = new AppsImpl(apiClient);
+    apps.list(new ListAppsRequest());
+
+    verify(apiClient)
+        .execute(
+            argThat((Request req) -> !req.getHeaders().containsKey("X-Databricks-Workspace-Id")),
+            any());
+  }
 }

databricks-sdk-java/src/test/java/com/databricks/sdk/service/billing/BudgetsImplTest.java

@@ -0,0 +1,33 @@
+package com.databricks.sdk.service.billing;
+
+import static org.mockito.ArgumentMatchers.*;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.databricks.sdk.core.ApiClient;
+import com.databricks.sdk.core.http.Request;
+import java.io.IOException;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+public class BudgetsImplTest {
+  // Account-scoped services must not forward the workspace routing header even
+  // when ApiClient#workspaceId() happens to be set. This locks in the generator
+  // gate (`if not .Service.IsAccounts`) so a regression that drops it would be
+  // caught here.
+  @Test
+  public void testWorkspaceIdHeaderNotSentForAccountScopedService() throws IOException {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    when(apiClient.workspaceId()).thenReturn("7474644166319138");
+    when(apiClient.configuredAccountID()).thenReturn("account-abc");
+    when(apiClient.execute(any(), any())).thenReturn(null);
+
+    BudgetsService budgets = new BudgetsImpl(apiClient);
+    budgets.list(new ListBudgetConfigurationsRequest());
+
+    verify(apiClient)
+        .execute(
+            argThat((Request req) -> !req.getHeaders().containsKey("X-Databricks-Workspace-Id")),
+            any());
+  }
+}