Add unpause method support (#261)

* Add unpause method support

Author: alyona007

api/src/main/java/com/messagebird/MessageBirdClient.java

@@ -105,6 +105,7 @@ public class MessageBirdClient {
     private static final String VOICELEGS_SUFFIX_PATH = "/legs";
     static final String FILES_PATH = "/files";
     static final String TEMPLATES_PATH = "/templates";
+    static final String UNPAUSE_TEMAPLATE_PATH = "/unpause";
     static final String OUTBOUND_SMS_PRICING_PATH = "/pricing/sms/outbound";
     static final String OUTBOUND_SMS_PRICING_SMPP_PATH = "/pricing/sms/outbound/smpp/%s";
 
@@ -2145,6 +2146,23 @@ public void deleteTemplatesBy(final String templateName)
         messageBirdService.delete(url, null);
     }
 
+    public void unpauseTemplatesByTemplateName(final String templateName)
+        throws UnauthorizedException, GeneralException {
+        if (templateName == null) {
+            throw new IllegalArgumentException("Template name must be specified.");
+        }
+
+        String url = String.format(
+                "%s%s%s%s/%s",
+                INTEGRATIONS_BASE_URL_V2,
+                INTEGRATIONS_WHATSAPP_PATH,
+                TEMPLATES_PATH,
+                UNPAUSE_TEMAPLATE_PATH,
+                templateName
+        );
+        messageBirdService.sendPayLoad("POST", url, "", null);
+    }
+
     /**
      * Function to create a child account
      *

api/src/main/java/com/messagebird/MessageBirdServiceImpl.java

@@ -382,6 +382,9 @@ <P> APIResponse doRequest(final String method, final String url, final Map<Strin
                 inputStream = connection.getInputStream();
             } else {
                 inputStream = connection.getErrorStream();
+                if (inputStream == null) {
+                    throw new IOException("Server returned HTTP error code " + status + " with no body.");
+                }
             }
 
             return new APIResponse(readToEnd(inputStream), status);

api/src/test/java/com/messagebird/MessageBirdClientTest.java

@@ -1592,5 +1592,25 @@ private ConversationSendRequest createDummyConversationRequest() {
         return request;
     }
 
+    @Test
+    public void testUnpauseTemplatesByTemplateName_Success() throws UnauthorizedException, GeneralException {
+        final Template template = TestUtil.createWhatsAppTemplate("sample_template_name", "ko");
+        MessageBirdService messageBirdServiceMock = mock(MessageBirdService.class);
+        MessageBirdClient messageBirdClientInjectMock = new MessageBirdClient(messageBirdServiceMock);
+        String url = String.format(
+                "%s%s%s%s/%s",
+                INTEGRATIONS_BASE_URL_V2,
+                INTEGRATIONS_WHATSAPP_PATH,
+                TEMPLATES_PATH,
+                UNPAUSE_TEMAPLATE_PATH,
+                "sample_template_name"
+        );
+        messageBirdClientInjectMock.unpauseTemplatesByTemplateName("sample_template_name");
+        verify(messageBirdServiceMock).sendPayLoad("POST", url, "", null);
+    }
 
-}
+    @Test(expected = GeneralException.class)
+    public void testUnpauseTemplatesByTemplateName_NotFound() throws UnauthorizedException, GeneralException {
+        messageBirdClient.unpauseTemplatesByTemplateName("foo");
+    }
+}