Now allows for empty content when creating or updating a file (#197).

Author: gmessner

src/main/java/org/gitlab4j/api/RepositoryFileApi.java

@@ -226,7 +226,14 @@ private Form createForm(RepositoryFile file, String branchName, String commitMes
         }
 
         addFormParam(form, "encoding", file.getEncoding(), false);
-        addFormParam(form, "content", file.getContent(), true);
+
+        // Cannot use addFormParam() as it does not accept an empty or whitespace only string
+        String content = file.getContent();
+        if (content == null) {
+            throw new IllegalArgumentException("content cannot be null");
+        }
+        form.param("content", content);
+
         addFormParam(form, "commit_message", commitMessage, true);
         return (form);
     }

src/test/java/org/gitlab4j/api/TestRepositoryApi.java

@@ -236,6 +236,21 @@ public void testCreateFileAndDeleteFile() throws GitLabApiException {
         gitLabApi.getRepositoryFileApi().deleteFile(TEST_FILEPATH, project.getId(), TEST_BRANCH_NAME, "Testing deleteFile().");
     }
 
+    @Test
+    public void testCreateFileWithEmptyContent() throws GitLabApiException {
+
+        Project project = gitLabApi.getProjectApi().getProject(TEST_NAMESPACE, TEST_PROJECT_NAME);
+        assertNotNull(project);
+
+        RepositoryFile file = new RepositoryFile();
+        file.setFilePath(TEST_FILEPATH);
+        file.setContent("");
+        RepositoryFile createdFile = gitLabApi.getRepositoryFileApi().createFile(file, project.getId(), TEST_BRANCH_NAME, "Testing createFile().");
+        assertNotNull(createdFile);
+
+        gitLabApi.getRepositoryFileApi().deleteFile(TEST_FILEPATH, project.getId(), TEST_BRANCH_NAME, "Testing deleteFile().");
+    }
+
     @Test
     public void testProtectBranch() throws GitLabApiException {