diff --git a/build/build.xml b/build/build.xml
index f9574a3d4d..75affb0f2d 100644
--- a/build/build.xml
+++ b/build/build.xml
@@ -56,7 +56,8 @@
 
 	<target name="test" depends="clean,prepare,composer">
 		<exec dir="."
-			command="phpunit --log-junit build/logs/phpunit.xml
+			command="phpBB/vendor/bin/phpunit
+			--log-junit build/logs/phpunit.xml
 			--coverage-clover build/logs/clover.xml
 			--coverage-html build/coverage"
 			passthru="true" />
@@ -64,7 +65,8 @@
 
 	<target name="test-slow" depends="clean,prepare,composer">
 		<exec dir="."
-			command="phpunit --log-junit build/logs/phpunit.xml
+			command="phpBB/vendor/bin/phpunit
+			--log-junit build/logs/phpunit.xml
 			--configuration phpunit.xml.all
 			--group slow
 			--coverage-clover build/logs/clover-slow.xml
diff --git a/git-tools/merge.php b/git-tools/merge.php
index 034bd2032c..41a96c0890 100755
--- a/git-tools/merge.php
+++ b/git-tools/merge.php
@@ -78,12 +78,12 @@ function work($pull_id, $remote)
 			add_remote($pull_user, 'phpbb3');
 			run("git fetch $pull_user");
 			run("git merge --no-ff $pull_user/$pull_branch");
-			run("phpunit");
+			run("phpBB/vendor/bin/phpunit");
 
 			run("git checkout develop");
 			run("git pull $remote develop");
 			run("git merge --no-ff develop-olympus");
-			run("phpunit");
+			run("phpBB/vendor/bin/phpunit");
 		break;
 
 		case 'develop':
@@ -93,7 +93,7 @@ function work($pull_id, $remote)
 			add_remote($pull_user, 'phpbb3');
 			run("git fetch $pull_user");
 			run("git merge --no-ff $pull_user/$pull_branch");
-			run("phpunit");
+			run("phpBB/vendor/bin/phpunit");
 		break;
 
 		default:
diff --git a/tests/RUNNING_TESTS.txt b/tests/RUNNING_TESTS.txt
index de9c751238..f33fa59dc2 100644
--- a/tests/RUNNING_TESTS.txt
+++ b/tests/RUNNING_TESTS.txt
@@ -95,7 +95,7 @@ Running
 Once the prerequisites are installed, run the tests from the project root
 directory (above phpBB):
 
-    $ phpunit
+    $ phpBB/vendor/bin/phpunit
 
 Slow tests
 --------------
@@ -105,7 +105,7 @@ Thus these tests are in the `slow` group, which is excluded by default. You can
 enable slow tests by copying the phpunit.xml.all file to phpunit.xml. If you
 only want the slow tests, run:
 
-    $ phpunit --group slow
+    $ phpBB/vendor/bin/phpunit --group slow
 
 More Information
 ================