diff --git a/.travis.yml b/.travis.yml
index 6cc3dcd..30be35b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,29 @@
 language: php
+
 php:
-  - 5.6
-  - 5.5
+# - 5.3 # requires old distro, see below
   - 5.4
-  - 5.3
-  - hhvm
+  - 5.5
+  - 5.6
+  - 7.0
+  - 7.1
+  - 7.2
+  - hhvm # ignore errors, see below
+
+# lock distro so future defaults will not break the build
+dist: trusty
+
+matrix:
+  include:
+    - php: 5.3
+      dist: precise
+  allow_failures:
+    - php: hhvm
+
+sudo: false
+
 install:
-  - composer install --prefer-source --no-interaction
+  - composer install --no-interaction
+
 script:
-  - php vendor/bin/phpunit --coverage-text
+  - vendor/bin/phpunit --coverage-text
diff --git a/README.md b/README.md
index efcb7b6..f2e9500 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,26 @@ The recommended way to install this library is [through composer](http://getcomp
 }
 ```
 
+This project aims to run on any platform and thus does not require any PHP
+extensions and supports running on legacy PHP 5.3 through current PHP 7+ and
+HHVM.
+It's *highly recommended to use PHP 7+* for this project.
+
+## Tests
+
+To run the test suite, you first need to clone this repo and then install all
+dependencies [through Composer](https://getcomposer.org):
+
+```bash
+$ composer install
+```
+
+To run the test suite, go to the project root and run:
+
+```bash
+$ php vendor/bin/phpunit
+```
+
 ## License
 
 Released under the terms of the permissive [MIT license](http://opensource.org/licenses/MIT).
diff --git a/composer.json b/composer.json
index 83eda52..7168e87 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,7 @@
         "clue/graph": "~0.9.0|~0.8.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~4.0"
+        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35"
     },
     "autoload": {
         "psr-4": {"Graphp\\Algorithms\\": "src/"}
diff --git a/tests/MaxFlow/EdmondsKarpTest.php b/tests/MaxFlow/EdmondsKarpTest.php
index 034087e..978cdf9 100644
--- a/tests/MaxFlow/EdmondsKarpTest.php
+++ b/tests/MaxFlow/EdmondsKarpTest.php
@@ -1,12 +1,11 @@
 <?php
 
 use Fhaculty\Graph\Exception\UnexpectedValueException;
-
 use Fhaculty\Graph\Graph;
-
 use Graphp\Algorithms\MaxFlow\EdmondsKarp as AlgorithmMaxFlowEdmondsKarp;
+use PHPUnit\Framework\TestCase;
 
-class EdmondsKarpTest extends PHPUnit_Framework_TestCase
+class EdmondsKarpTest extends TestCase
 {
     public function testEdgeDirected()
     {
diff --git a/tests/MaximumMatching/FlowTest.php b/tests/MaximumMatching/FlowTest.php
index 8ea7f24..dbf03b5 100644
--- a/tests/MaximumMatching/FlowTest.php
+++ b/tests/MaximumMatching/FlowTest.php
@@ -1,12 +1,11 @@
 <?php
 
 use Fhaculty\Graph\Graph;
-
-use Graphp\Algorithms\MaximumMatching\Flow;
-
 use Fhaculty\Graph\Loader\EdgeListBipartit;
+use Graphp\Algorithms\MaximumMatching\Flow;
+use PHPUnit\Framework\TestCase;
 
-class FlowTest extends PHPUnit_Framework_TestCase
+class FlowTest extends TestCase
 {
 //     /**
 //      * run algorithm with small graph and check result against known result
diff --git a/tests/ShortestPath/MooreBellmanFordTest.php b/tests/ShortestPath/MooreBellmanFordTest.php
index af2c988..3c2138b 100644
--- a/tests/ShortestPath/MooreBellmanFordTest.php
+++ b/tests/ShortestPath/MooreBellmanFordTest.php
@@ -56,6 +56,8 @@ public function testUndirectedNegativeWeightIsCycle()
         $alg = $this->createAlg($v1);
 
         $cycle = $alg->getCycleNegative();
+
+        $this->assertInstanceOf('Fhaculty\Graph\Walk', $cycle);
     }
 
     public function testLoopNegativeWeightIsCycle()
@@ -68,6 +70,8 @@ public function testLoopNegativeWeightIsCycle()
         $alg = $this->createAlg($v1);
 
         $cycle = $alg->getCycleNegative();
+
+        $this->assertInstanceOf('Fhaculty\Graph\Walk', $cycle);
     }
 
     public function testNegativeComponentHasCycle()
@@ -90,7 +94,16 @@ public function testNegativeComponentHasCycle()
 
         // first component does not have a cycle
         $alg = $this->createAlg($v1);
-        $this->setExpectedException('UnderflowException');
+        $this->expectException('UnderflowException');
         $alg->getCycleNegative();
     }
+
+    public function expectException($class)
+    {
+        if (method_exists($this, 'setExpectedException')) {
+            $this->setExpectedException($class);
+        } else {
+            parent::expectException($class);
+        }
+    }
 }
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 0e3be73..b211810 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -5,10 +5,11 @@
 use Fhaculty\Graph\Graph;
 use Fhaculty\Graph\Vertex;
 use Fhaculty\Graph\Set\Vertices;
+use PHPUnit\Framework\TestCase as BaseTestCase;
 
 (include_once __DIR__ . '/../vendor/autoload.php') OR die(PHP_EOL . 'ERROR: composer autoloader not found, run "composer install" or see README for instructions' . PHP_EOL);
 
-class TestCase extends PHPUnit_Framework_TestCase
+class TestCase extends BaseTestCase
 {
     protected function assertGraphEquals(Graph $expected, Graph $actual)
     {
@@ -28,11 +29,8 @@ protected function assertGraphEquals(Graph $expected, Graph $actual)
         // do not use assertVertexEquals() in order to not increase assertion counter
 
         foreach ($expected->getVertices()->getMap() as $vid => $vertex) {
-            try {
-                $other = $actual->getVertex($vid);
-            } catch (Exception $e) {
-                $this->fail();
-            }
+            $other = $actual->getVertex($vid);
+
             if ($this->getVertexDump($vertex) !== $this->getVertexDump($vertex)) {
                 $this->fail();
             }