diff --git a/system/HTTP/Negotiate.php b/system/HTTP/Negotiate.php
index 7af05b35b701..1a0aa7be7e6b 100644
--- a/system/HTTP/Negotiate.php
+++ b/system/HTTP/Negotiate.php
@@ -1,4 +1,6 @@
-<?php namespace CodeIgniter\HTTP;
+<?php
+
+namespace CodeIgniter\HTTP;
 
 /**
  * CodeIgniter
@@ -35,7 +37,6 @@
  * @since	Version 3.0.0
  * @filesource
  */
-
 use CodeIgniter\HTTP\Exceptions\HTTPException;
 
 /**
@@ -211,13 +212,6 @@ protected function getBestMatch(array $supported, string $header = null, bool $e
 
 		$acceptable = $this->parseHeader($header);
 
-		// If no acceptable values exist, return the
-		// first that we support.
-		if (count($acceptable) === 0)
-		{
-			return $supported[0];
-		}
-
 		foreach ($acceptable as $accept)
 		{
 			// if acceptable quality is zero, skip it.
@@ -290,8 +284,8 @@ public function parseHeader(string $header)
 			}
 
 			$results[] = [
-				'value'	 => trim($value),
-				'q'		 => (float) $quality,
+				'value' => trim($value),
+				'q' => (float) $quality,
 				'params' => $parameters
 			];
 		}
diff --git a/system/HTTP/RedirectResponse.php b/system/HTTP/RedirectResponse.php
index e4136ed89ec9..02a3ef8f9caa 100644
--- a/system/HTTP/RedirectResponse.php
+++ b/system/HTTP/RedirectResponse.php
@@ -190,10 +190,13 @@ protected function ensureSession()
 		$session = Services::session();
 
 		// Ensure we have the session started up.
+		// true for travis-ci, so not coverable
+		// @codeCoverageIgnoreStart
 		if ( ! isset($_SESSION))
 		{
 			$session->start();
 		}
+		// @codeCoverageIgnoreEnd
 
 		return $session;
 	}
diff --git a/tests/system/HTTP/NegotiateTest.php b/tests/system/HTTP/NegotiateTest.php
index 4dbeefc39c14..dffc6b32e0cc 100644
--- a/tests/system/HTTP/NegotiateTest.php
+++ b/tests/system/HTTP/NegotiateTest.php
@@ -146,28 +146,44 @@ public function testBestMatchEmpty()
 
 	public function testBestMatchNoHeader()
 	{
-		$this->request->setHeader('Accept','');
+		$this->request->setHeader('Accept', '');
 		$this->assertEquals('', $this->negotiate->media(['apple', 'banana'], true));
 		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'banana/yellow'], false));
 	}
 
 	public function testBestMatchNotAcceptable()
 	{
-		$this->request->setHeader('Accept','popcorn/cheddar');
-		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'banana/yellow'],false));
+		$this->request->setHeader('Accept', 'popcorn/cheddar');
+		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'banana/yellow'], false));
+		$this->assertEquals('banana/yellow', $this->negotiate->media(['banana/yellow', 'apple/mac'], false));
 	}
 
 	public function testBestMatchFirstSupported()
 	{
-		$this->request->setHeader('Accept','popcorn/cheddar, */*');
-		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'banana/yellow'],false));
+		$this->request->setHeader('Accept', 'popcorn/cheddar, */*');
+		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'banana/yellow'], false));
 	}
 
 	public function testBestMatchLowQuality()
 	{
-		$this->request->setHeader('Accept','popcorn/cheddar;q=0, apple/mac, */*');
-		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'popcorn/cheddar'],false));
-		$this->assertEquals('apple/mac', $this->negotiate->media(['popcorn/cheddar','apple/mac'],false));
+		$this->request->setHeader('Accept', 'popcorn/cheddar;q=0, apple/mac, */*');
+		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'popcorn/cheddar'], false));
+		$this->assertEquals('apple/mac', $this->negotiate->media(['popcorn/cheddar', 'apple/mac'], false));
+	}
+
+	public function testBestMatchOnlyLowQuality()
+	{
+		$this->request->setHeader('Accept', 'popcorn/cheddar;q=0');
+		// the first supported should be returned, since nothing will make us happy
+		$this->assertEquals('apple/mac', $this->negotiate->media(['apple/mac', 'popcorn/cheddar'], false));
+		$this->assertEquals('popcorn/cheddar', $this->negotiate->media(['popcorn/cheddar', 'apple/mac'], false));
+	}
+
+	public function testParameterMatching()
+	{
+		$this->request->setHeader('Accept', 'popcorn/cheddar;a=0;b=1');
+		$this->assertEquals('popcorn/cheddar;a=2', $this->negotiate->media(['popcorn/cheddar;a=2'], false));
+		$this->assertEquals('popcorn/cheddar;a=0', $this->negotiate->media(['popcorn/cheddar;a=0', 'popcorn/cheddar;a=2;b=1'], false));
 	}
 
 }
diff --git a/tests/system/HTTP/RedirectResponseTest.php b/tests/system/HTTP/RedirectResponseTest.php
index d292aad6057e..fece957954a1 100644
--- a/tests/system/HTTP/RedirectResponseTest.php
+++ b/tests/system/HTTP/RedirectResponseTest.php
@@ -1,4 +1,6 @@
-<?php namespace CodeIgniter\HTTP;
+<?php
+
+namespace CodeIgniter\HTTP;
 
 use Config\App;
 use Config\Autoload;
@@ -10,11 +12,10 @@
 
 class RedirectResponseTest extends \CIUnitTestCase
 {
+
 	/** @var RouteCollection */
 	protected $routes;
-
 	protected $request;
-
 	protected $config;
 
 	public function setUp()
@@ -47,14 +48,25 @@ public function testRedirectRoute()
 	{
 		$response = new RedirectResponse(new App());
 
-		$this->routes->add( 'exampleRoute', 'Home::index' );
+		$this->routes->add('exampleRoute', 'Home::index');
 
-		$response->route( 'exampleRoute' );
+		$response->route('exampleRoute');
 
 		$this->assertTrue($response->hasHeader('Location'));
 		$this->assertEquals('http://example.com/exampleRoute', $response->getHeaderLine('Location'));
 	}
 
+	public function testRedirectRouteBad()
+	{
+		$this->expectException(Exceptions\HTTPException::class);
+
+		$response = new RedirectResponse(new App());
+
+		$this->routes->add('exampleRoute', 'Home::index');
+
+		$response->route('differentRoute');
+	}
+
 	public function testRedirectRelativeConvertsToFullURI()
 	{
 		$response = new RedirectResponse($this->config);
@@ -97,7 +109,7 @@ public function testWithValidationErrors()
 
 		$validation = $this->createMock(Validation::class);
 		$validation->method('getErrors')
-		           ->willReturn(['foo' =>'bar']);
+				->willReturn(['foo' => 'bar']);
 
 		Services::injectMock('validation', $validation);
 
@@ -154,4 +166,36 @@ public function testRedirectWithQueryOnly()
 		$this->assertTrue($response->hasHeader('Location'));
 		$this->assertEquals('http://example.com/foo?foo=bar', $response->getHeaderLine('Location'));
 	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function testRedirectBack()
+	{
+		$_SERVER['HTTP_REFERER'] = 'http://somewhere.com';
+		$this->request = new MockIncomingRequest($this->config, new URI('http://somewhere.com'), null, new UserAgent());
+		Services::injectMock('request', $this->request);
+
+		$response = new RedirectResponse(new App());
+		
+		$returned = $response->back();
+		$this->assertEquals('http://somewhere.com', $returned->getHeader('location')->getValue());
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function testRedirectBackMissing()
+	{
+		$_SESSION = [];
+
+		$response = new RedirectResponse(new App());
+
+		$returned = $response->back();
+
+		$this->assertSame($response, $returned);
+	}
+
 }