refactor thrown exceptions to be more specific than just Exception class

.travis.yml

@@ -0,0 +1,25 @@
+language: php
+
+sudo: false
+
+cache:
+    directories:
+        - $HOME/.composer/cache
+
+php:
+    - 5.6
+    - 7.0
+
+branches:
+  only:
+  - /^dev-.*$/
+  - phpunit-support
+
+before_install:
+    - travis_retry composer self-update
+
+install:
+    - travis_retry composer update ${COMPOSER_FLAGS} --prefer-source --no-interaction
+
+script:
+    - composer test-ci

composer.json

@@ -32,5 +32,10 @@
     "psr-4": {
       "Tests\\": "tests/"
     }
+  },
+  "scripts": {
+    "test": "vendor/bin/phpunit",
+    "test-ci": "vendor/bin/phpunit --coverage-clover report/coverage.xml",
+    "test-coverage": "vendor/bin/phpunit --coverage-html report/html"
   }
 }

phpunit.xml

@@ -15,17 +15,6 @@
         <directory suffix="Test.php">./tests/*</directory>
     </testsuite>
 
-    <logging>
-        <log type="coverage-html"
-             target="report/coverage"
-             charset="UTF-8"
-             yui="true"
-             highlight="true"
-             lowUpperBound="35"
-             highLowerBound="70"/>
-        <log type="junit" target="report/junit.xml" logIncompleteSkipped="false"/>
-    </logging>
-
     <filter>
         <whitelist processUncoveredFilesFromWhitelist="true">
             <directory suffix=".php">src</directory>