diff --git a/src/MathMathML.php b/src/MathMathML.php
index 9cae460..904c164 100644
--- a/src/MathMathML.php
+++ b/src/MathMathML.php
@@ -38,13 +38,12 @@ class MathMathML extends MathRenderer {
 		$this->setMode( 'mathml' );
 		$this->hosts = $wgMathMathMLUrl;
 		if ( isset( $params['type'] ) ) {
+			$allowedTypes = [ 'pmml', 'ascii', 'chem' ];
+			if ( in_array( $params['type'], $allowedTypes ) ) {
+				$this->inputType = $params['type'];
+			}
 			if ( $params['type'] == 'pmml' ) {
-				$this->inputType = 'pmml';
 				$this->setMathml( '<math>' . $tex . '</math>' );
-			} elseif ( $params['type'] == 'ascii' ) {
-				$this->inputType = 'ascii';
-			} elseif ( $params['type'] == 'chem' ) {
-				$this->inputType = 'chem';
 			}
 		}
 		if ( !isset( $params['display'] ) && $this->getMathStyle() == 'inlineDisplaystyle' ) {
@@ -194,7 +193,7 @@ class MathMathML extends MathRenderer {
 		$error = '';
 		$res = null;
 		if ( !$host ) {
-			$host = self::pickHost();
+			$host = $this->pickHost();
 		}
 		if ( !$post ) {
 			$this->getPostData();
@@ -237,10 +236,11 @@ class MathMathML extends MathRenderer {
 	 * If more than one demon is available, one is chosen at random.
 	 *
 	 * @return string
+	 * @deprecated
 	 */
 	protected function pickHost() {
 		if ( is_array( $this->hosts ) ) {
-			$host = array_rand( $this->hosts );
+			$host = $this->hosts[array_rand( $this->hosts )];
 			$this->hosts = $host; // Use the same host for this class instance
 		} else {
 			$host = $this->hosts;
@@ -278,7 +278,7 @@ class MathMathML extends MathRenderer {
 			return false;
 		}
 		$res = '';
-		$host = self::pickHost();
+		$host = $this->pickHost();
 		$post = $this->getPostData();
 		$this->lastError = '';
 		$requestResult = $this->makeRequest( $host, $post, $res, $this->lastError );
@@ -337,15 +337,11 @@ class MathMathML extends MathRenderer {
 		} else {
 			$name = $xmlObject->getRootElement();
 			$elementSplit = explode( ':', $name );
-			if ( is_array( $elementSplit ) ) {
-				$localName = end( $elementSplit );
-			} else {
-				$localName = $name;
-			}
+			$localName = end( $elementSplit );
 			if ( in_array( $localName, $this->getAllowedRootElements() ) ) {
 				$out = true;
 			} else {
-				LoggerFactory::getInstance( 'Math' )->error( "Got wrong root element : $name" );
+				LoggerFactory::getInstance( 'Math' )->error( "Got wrong root element: $name" );
 			}
 		}
 		return $out;
diff --git a/tests/phpunit/MathMathMLTest.php b/tests/phpunit/MathMathMLTest.php
index 362ea7b..8423e52 100644
--- a/tests/phpunit/MathMathMLTest.php
+++ b/tests/phpunit/MathMathMLTest.php
@@ -32,10 +32,30 @@ class MathMathMLTest extends MediaWikiTestCase {
 	}
 
 	protected function setUp() {
-		parent::setUp(); // TODO: Change the autogenerated stub
+		parent::setUp();
 		$this->setMwGlobals( 'wgMathoidCli', false );
 	}
 
+	/**@covers MathMathML::__constructor */
+	public function testMathMLConstructorWithPmml() {
+		$mml = new MathMathML( '<mo>sin</mo>', [ 'type' => 'pmml' ] );
+		$this->assertEquals( 'pmml', $mml->getInputType() );
+		$this->assertEquals( '<math><mo>sin</mo></math>', $mml->getMathml() );
+	}
+
+	/**@covers MathMathML::__constructor */
+	public function testMathMLConstructorWithInvalidType() {
+		$mml = new MathMathML( '<mo>sin</mo>', [ 'type' => 'invalid' ] );
+		$this->assertEquals( 'tex', $mml->getInputType() );
+	}
+
+	/**@covers MathMathML::__constructor */
+	public function testChangeRootElemts() {
+		$mml = new MathMathML( '<mo>sin</mo>', [ 'type' => 'invalid' ] );
+		$mml->setAllowedRootElements( [ 'a','b' ] );
+		$this->assertEquals( [ 'a','b' ], $mml->getAllowedRootElements() );
+	}
+
 	/**
 	 * Tests behavior of makeRequest() that communicates with the host.
 	 * Testcase: Invalid request.
@@ -102,6 +122,38 @@ class MathMathMLTest extends MediaWikiTestCase {
 		$this->assertContains( $errmsg, $error, "timeout call errormessage" );
 	}
 
+	/**
+	 * Tests behavior of makeRequest() that communicates with the host.
+	 * Test case: Get PostData.
+	 * @covers MathMathML::makeRequest
+	 */
+	public function testMakeRequestGetPostData() {
+		self::setMockValues( false, true, true );
+		$url = 'http://example.com/timeout';
+		$renderer = $this->getMockBuilder( 'MathMathML' )
+			->setMethods( [ 'getPostData' ] )
+			->disableOriginalConstructor()
+			->getMock();
+		$renderer->expects( $this->once() )->method( 'getPostData' );
+		$renderer->makeRequest( $url, false, $res, $error, 'MathMLHttpRequestTester' );
+	}
+
+	/**
+	 * Tests behavior of makeRequest() that communicates with the host.
+	 * Test case: Get host.
+	 * @covers MathMathML::pickHost
+	 */
+	public function testMakeRequestGetHost() {
+		self::setMockValues( false, true, true );
+		$url = 'http://example.com/timeout';
+		$renderer = $this->getMockBuilder( 'MathMathML' )
+			->setMethods( [ 'getPostData', 'pickHost' ] )
+			->disableOriginalConstructor()
+			->getMock();
+		$renderer->expects( $this->once() )->method( 'pickHost' );
+		$renderer->makeRequest( false, false, $res, $error, 'MathMLHttpRequestTester' );
+	}
+
 	/**
 	 * Checks if a String is a valid MathML element
 	 * @covers MathMathML::isValidMathML
@@ -119,6 +171,22 @@ class MathMathMLTest extends MediaWikiTestCase {
 			'test if math expression is invalid mathml sample' );
 	}
 
+	/**
+	 * @covers MathMathML::isValidMathML
+	 */
+	public function testInvalidXml() {
+		$renderer = $this->getMockBuilder( 'MathMathML' )
+			->setMethods( null )
+			->disableOriginalConstructor()
+			->getMock();
+		$invalidSample = '<mat';
+		$this->assertFalse( $renderer->isValidMathML( $invalidSample ),
+			'test if math expression is invalid mathml sample' );
+		$renderer->setXMLValidation( false );
+		$this->assertTrue( $renderer->isValidMathML( $invalidSample ),
+			'test if math expression is invalid mathml sample' );
+	}
+
 	public function testintegrationTestWithLinks() {
 		$p = new Parser();
 		$po = new ParserOptions();
@@ -141,6 +209,26 @@ class MathMathMLTest extends MediaWikiTestCase {
 		$m->setSvg( 'style=" vertical-align:-.505ex; \n" height="2.843ex" width="28.527ex"' );
 		$this->assertEquals( 'vertical-align:-.505ex; height: 2.843ex; width: 28.527ex;', $style );
 	}
+
+	public function testPickHost() {
+		$hosts = [ 'a', 'b', 'c' ];
+		$this->setMwGlobals( 'wgMathMathMLUrl', $hosts );
+		$class = new ReflectionClass( 'MathMathML' );
+		$method = $class->getMethod( 'pickHost' );
+		$method->setAccessible( true );
+		srand( 0 ); // Make array_rand always return the same elements
+		$h1 = $hosts[array_rand( $hosts )];
+		$h2 = $hosts[array_rand( $hosts )];
+		srand( 0 );
+		$m = new MathMathML();
+		$host1 = $method->invoke( $m, [] );
+		$this->assertEquals( $h1, $host1 );
+		$host2 = $method->invoke( $m, [] );
+		$this->assertEquals( $host1, $host2 );
+		$m2 = new MathMathML();
+		$host3 = $method->invoke( $m2, [] );
+		$this->assertEquals( $h2, $host3 );
+	}
 }
 
 /**