Fix tests.

Author: kishorenc

src/main/java/org/typesense/api/ApiCall.java

@@ -43,6 +43,7 @@ public ApiCall(Configuration configuration) {
         this.nodes = configuration.nodes;
         this.apiKey = configuration.apiKey;
         this.retryInterval = configuration.retryInterval;
+        nodeIndex = 0;
 
         mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
         mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);

src/main/java/org/typesense/api/Documents.java

@@ -40,7 +40,7 @@ public String create(Map<String, Object> document, ImportDocumentsParameters que
 
     public Map<String, Object> upsert(Map<String, Object> document) throws Exception {
         ImportDocumentsParameters queryParameters = new ImportDocumentsParameters();
-        queryParameters.action("upsert");
+        queryParameters.action(ImportDocumentsParameters.ActionEnum.UPSERT);
 
         return this.apiCall.post(getEndPoint("/"),document,queryParameters,Map.class);
     }

src/test/java/org/typesense/api/DocumentsTest.java

@@ -182,7 +182,7 @@ void testImport() throws Exception {
 
         documentList.add(document1);
         documentList.add(document2);
-        queryParameters.action("create");
+        queryParameters.action(ImportDocumentsParameters.ActionEnum.CREATE);
 
         String countriesImport = this.client.collections("books").documents()
                 .import_(documentList, queryParameters);
@@ -192,7 +192,7 @@ void testImport() throws Exception {
     @Test
     void testImportAsString() throws Exception {
         ImportDocumentsParameters queryParameters = new ImportDocumentsParameters();
-        queryParameters.action("create");
+        queryParameters.action(ImportDocumentsParameters.ActionEnum.CREATE);
         String documentList = "{\"countryName\": \"India\", \"capital\": \"Washington\", \"gdp\": 5215}\n" +
                 "{\"countryName\": \"Iran\", \"capital\": \"London\", \"gdp\": 5215}";
         String booksImport = this.client.collections("books").documents().import_(documentList, queryParameters);
@@ -215,7 +215,7 @@ void testDirtyCreate() throws Exception {
 
         ImportDocumentsParameters queryParameters = new ImportDocumentsParameters();
         queryParameters.dirtyValues(ImportDocumentsParameters.DirtyValuesEnum.COERCE_OR_REJECT);
-        queryParameters.action("upsert");
+        queryParameters.action(ImportDocumentsParameters.ActionEnum.UPSERT);
 
         String[] authors = {"shakspeare", "william"};
         HashMap<String, Object> hmap = new HashMap<>();
@@ -245,7 +245,7 @@ void testNestedObjectImport() throws Exception {
         client.collections().create(collectionSchema);
 
         ImportDocumentsParameters queryParameters = new ImportDocumentsParameters();
-        queryParameters.action("create");
+        queryParameters.action(ImportDocumentsParameters.ActionEnum.CREATE);
 
         List<NestedDocument> docs = new ArrayList<>();
         NestedDocument doc = new NestedDocument("LA", "CA", "USA")