Add test suite and Travis CI config

The test was initially failing because bin/coverage-check was not
marked as executable. This commit fixes that as well.

Author: Krinkle

.travis.yml

@@ -0,0 +1,9 @@
+sudo: false
+language: php
+php:
+  - "7.2"
+  - "7.1"
+  - "7.0"
+  - "5.6"
+  - "5.5"
+script: ./test/run

bin/coverage-check

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<coverage generated="1001">
+  <project timestamp="1001">
+    <package name="Example">
+      <file name="/tmp/Example/String.php">
+        <class name="Example\String" namespace="Example">
+          <metrics complexity="15" methods="5" coveredmethods="4" conditionals="0" coveredconditionals="0" statements="33" coveredstatements="32" elements="38" coveredelements="36"/>
+        </class>
+        <metrics loc="129" ncloc="62" classes="1" methods="5" coveredmethods="4" conditionals="0" coveredconditionals="0" statements="33" coveredstatements="32" elements="38" coveredelements="36"/>
+      </file>
+      <file name="/tmp/Example/StringList.php">
+        <class name="Example\StringList" namespace="Example">
+          <metrics complexity="8" methods="5" coveredmethods="4" conditionals="0" coveredconditionals="0" statements="19" coveredstatements="16" elements="24" coveredelements="20"/>
+        </class>
+        <metrics loc="103" ncloc="45" classes="1" methods="5" coveredmethods="4" conditionals="0" coveredconditionals="0" statements="19" coveredstatements="16" elements="24" coveredelements="20"/>
+      </file>
+    </package>
+    <metrics files="2" loc="232" ncloc="107" classes="2" methods="10" coveredmethods="8" conditionals="0" coveredconditionals="0" statements="52" coveredstatements="48" elements="62" coveredelements="56"/>
+  </project>
+</coverage>

test/clover.xml

@@ -0,0 +1,12 @@
+#!/bin/bash -eu
+
+# Consistent CWD, regardless of which directory the script is run from.
+cd $(dirname $0)/..
+
+# Expect pass
+bin/coverage-check test/clover.xml 0
+bin/coverage-check test/clover.xml 90
+
+# Expect fail
+! bin/coverage-check test/clover.xml 95
+! bin/coverage-check test/clover.xml 100