Fix issue #299: calling expectsJson() before body() breaks response parsing

src/Httpful/Request.php

@@ -343,13 +343,12 @@ public function authenticateWithCert($cert, $key, $passphrase = null, $encoding
     /**
      * Set the body of the request
      * @param mixed $payload
-     * @param string $mimeType currently, sets the sends AND expects mime type although this
-     *    behavior may change in the next minor release (as it is a potential breaking change).
+     * @param string $mimeType $mimeType sets the Content-Type for the request body (does not affect expected response type)
      * @return Request
      */
     public function body($payload, $mimeType = null)
     {
-        $this->mime($mimeType);
+        $this->contentType($mimeType);
         $this->payload = $payload;
         // Iserntentially don't call _serializePayload yet.  Wait until
         // we actually send off the request to convert payload to string.

tests/Httpful/HttpfulTest.php

@@ -529,6 +529,49 @@ public function testShorthandMimeDefinition()
         $this->assertEquals(Mime::JSON, $r->expected_type);
     }
 
+    /**
+     * Test that expectsJson() before body() correctly preserves expected response type
+     * This fixes issue #299: calling expectsJson() before body() should not break response parsing.
+     */
+    public function testExpectsJsonBeforeBodyPreservesExpectedType()
+    {
+        // Simulate the issue: expectsJson() then body() with FORM mime type
+        $req = Request::post('http://example.com/')
+            ->expectsJson()
+            ->body(['abc' => 123], Mime::FORM);
+
+
+        // verify that expected_type is still JSON (not overwritten to FORM)
+        $this->assertEquals(Mime::JSON, $req->expected_type);
+
+        // Verify that content_type is FORM (for the request body)
+        $this->assertEquals(Mime::FORM, $req->content_type);
+
+        // create a mock JSON response to verify it parses correctly
+        $jsonResponse = '{"exampleResponseFromServer": "data processed successfully"}';
+        $response = new Response($jsonResponse, self::SAMPLE_JSON_HEADER, $req);
+
+        // The response should be parsed as JSON (not as form data)
+        $this->assertIsObject($response->body);
+        $this->assertEquals('data processed successfully', $response->body->exampleResponseFromServer);
+    }
+
+    /**
+     * Test that body() with mime type only sets content_type, not expected_type
+     */
+    public function testBodyOnlySetsContentType()
+    {
+        $req = Request::post('http://example.com/')
+            ->expectsXml()
+            ->body(['key' => 'value'], Mime::JSON);
+
+            // expected_type should remain XML
+            $this->assertEquals(Mime::XML, $req->expected_type);
+
+            // content_type should be JSON (for the request body)
+            $this->assertEquals(Mime::JSON, $req->content_type);
+    }
+
     public function testOverrideXmlHandler()
     {
         // Lazy test...