diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..97084d0
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- https://phpunit.readthedocs.io/en/latest/configuration.html -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="./tests/bootstrap.php"
+         convertDeprecationsToExceptions="false"
+>
+    <php>
+        <ini name="display_errors" value="1" />
+        <ini name="error_reporting" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="TreeWalker Test Suite">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <coverage cacheDirectory="coverage"
+              includeUncoveredFiles="true"
+              processUncoveredFiles="true"
+              pathCoverage="false"
+              ignoreDeprecatedCodeUnits="true"
+              disableCodeCoverageIgnore="true">
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+        <exclude>
+            <directory>tests</directory>
+        </exclude>
+        <report>
+            <text outputFile="php://stdout"/>
+            <clover outputFile="coverage/clover.xml"/>
+            <cobertura outputFile="coverage/cobertura.xml"/>
+        </report>
+    </coverage>
+</phpunit>