diff --git a/Dockerfile b/Dockerfile
index b5413a3..1e8dbdb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,8 @@
 FROM php:7.2.0-cli
-WORKDIR /opt/php
+WORKDIR /app
 RUN apt-get update \
-    && apt-get install -y zlib1g-dev wget git-core \
-    && docker-php-ext-install zip
-ADD . /opt/php
-CMD [ "./docker/test_runner.sh" ]
+    && apt-get install -y zlib1g-dev wget git-core python-pip \
+    && docker-php-ext-install zip \
+    && pip install Sphinx
+ADD . /app
+CMD [ "make", "cs", "test" ]
diff --git a/Makefile b/Makefile
index c3841a2..ff8edc0 100644
--- a/Makefile
+++ b/Makefile
@@ -191,14 +191,11 @@ pseudoxml:
 	@echo
 	@echo "Build finished. The pseudo-XML files are in $(BUILDDIR)/pseudoxml."
 
-composer.phar:
-	php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
-	php -r "if (hash_file('SHA384', 'composer-setup.php') === 'e115a8dc7871f15d853148a7fbac7da27d6c0030b848d9b3dc09e2a0388afed865e6a3d6b3c0fad45c48e2b5fc1196ae') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
-	php composer-setup.php
-	php -r "unlink('composer-setup.php');"
-
 install: vendor
 
+composer.phar:
+	docker/install-composer.sh
+
 vendor: composer.phar
 	php composer.phar install
 
diff --git a/docker-compose.yml b/docker-compose.yml
index 1242ae2..af6b1cc 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -5,12 +5,4 @@ services:
       context: .
       dockerfile: Dockerfile
     volumes:
-      - .:/opt/php
-    command: ["/opt/php/docker/test_runner.sh"]
-  composer:
-    image: composer:latest
-    working_dir: /app
-    volumes:
-       - .:/app
-    command:
-      - install
+      - .:/app
diff --git a/docker/install-composer.sh b/docker/install-composer.sh
new file mode 100755
index 0000000..d39d20a
--- /dev/null
+++ b/docker/install-composer.sh
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+EXPECTED_SIGNATURE="$(wget -q -O - https://composer.github.io/installer.sig)"
+php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
+ACTUAL_SIGNATURE="$(php -r "echo hash_file('SHA384', 'composer-setup.php');")"
+
+if [ "$EXPECTED_SIGNATURE" != "$ACTUAL_SIGNATURE" ]
+then
+    >&2 echo 'ERROR: Invalid installer signature'
+    rm composer-setup.php
+    exit 1
+fi
+
+php composer-setup.php --quiet
+RESULT=$?
+rm composer-setup.php
+exit $RESULT
diff --git a/docker/test_runner.sh b/docker/test_runner.sh
deleted file mode 100755
index 6ce56da..0000000
--- a/docker/test_runner.sh
+++ /dev/null
@@ -1,28 +0,0 @@
-#!/bin/sh
-
-echo "Installing composer..."
-EXPECTED_SIGNATURE=$(wget -q -O - https://composer.github.io/installer.sig)
-php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
-ACTUAL_SIGNATURE=$(php -r "echo hash_file('SHA384', 'composer-setup.php');")
-
-if [ "$EXPECTED_SIGNATURE" != "$ACTUAL_SIGNATURE" ]
-then
-    >&2 echo 'ERROR: Invalid installer signature'
-    rm composer-setup.php
-    exit 1
-fi
-
-php composer-setup.php --quiet
-rm composer-setup.php
-
-echo "Downloading dependencies using composer..."
-php composer.phar install --prefer-dist --no-interaction
-
-echo "Running tests..."
-if ./vendor/bin/phpunit; then
-  echo "Tests passed successfully!"
-  exit 0
-else
-  echo "Tests failed :("
-  exit 1
-fi