feat(datastore): support --use-firestore-in-datastore-mode in the datastore emulator

Fixes #1406
This followed the changes in the java-datastore library. See
googleapis/java-datastore#1698

Author: diegomarquezp

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/datastore/EmulatorSettings.java

@@ -54,6 +54,20 @@ public class EmulatorSettings {
    */
   private Path dataDir;
 
+  /**
+   * Configures whether the emulator runs in "Cloud Firestore in Datastore Mode". Correspondent CLI
+   * property: --use-firestore-in-datastore-mode.
+   */
+  private boolean firestoreInDatastoreMode = false;
+
+  public boolean getFirestoreInDatastoreMode() {
+    return firestoreInDatastoreMode;
+  }
+
+  public void setFirestoreInDatastoreMode(boolean useFirestoreInDatastoreMode) {
+    this.firestoreInDatastoreMode = useFirestoreInDatastoreMode;
+  }
+
   public Path getDataDir() {
     return dataDir;
   }

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/datastore/GcpDatastoreEmulatorAutoConfiguration.java

@@ -58,6 +58,7 @@ public LocalDatastoreHelper createDatastoreHelper(GcpDatastoreProperties datasto
             .setPort(settings.getPort())
             .setStoreOnDisk(settings.isStoreOnDisk())
             .setDataDir(settings.getDataDir())
+            .setFirestoreInDatastoreMode(settings.getFirestoreInDatastoreMode())
             .build();
 
     return this.helper;

spring-cloud-gcp-autoconfigure/src/test/java/com/google/cloud/spring/autoconfigure/datastore/GcpDatastoreEmulatorAutoConfigurationTests.java

@@ -42,7 +42,8 @@ void testDatastoreOptionsCorrectlySet() {
             "spring.cloud.gcp.datastore.emulator.enabled=true",
             "spring.cloud.gcp.datastore.emulator.consistency=0.8",
             "spring.cloud.gcp.datastore.emulator.dataDir=/usr/local/datastore",
-            "spring.cloud.gcp.datastore.emulator.storeOnDisk=false")
+            "spring.cloud.gcp.datastore.emulator.storeOnDisk=false",
+            "spring.cloud.gcp.datastore.emulator.firestoreInDatastoreMode=true")
         .run(
             context -> {
               LocalDatastoreHelper helper = context.getBean(LocalDatastoreHelper.class);
@@ -51,6 +52,7 @@ void testDatastoreOptionsCorrectlySet() {
               assertThat(helper.getConsistency()).isEqualTo(0.8D);
               assertThat(helper.getGcdPath()).isEqualTo(Paths.get("/usr/local/datastore"));
               assertThat(helper.isStoreOnDisk()).isFalse();
+              assertThat(helper.isFirestoreInDatastoreMode()).isTrue();
             });
   }