Check for composer installation failure (#924)

tests/run.sh

@@ -2,12 +2,17 @@
 
 set -x
 
+errors=()
+
 if [[ "${CI}" == "true" ]]; then
     composer self-update
     composer install --prefer-source --no-interaction
+    if [[ "${?}" -ne 0 ]]; then
+        echo "Error: composer install failed"
+        errors+=("composer install failed")
+    fi
 fi
 
-
 # Use composer's phpunit and phpcs by adding composer bin directory to the path environment variable.
 export PATH="${PWD}/vendor/bin:${PATH}"
 
@@ -21,8 +26,6 @@ echo "CI_PHP_FUTURE_RELEASE: ${CI_PHP_FUTURE_RELEASE}"
 php -r "var_dump(phpversion());"
 php -r "var_dump(curl_version());"
 
-errors=()
-
 source "run_syntax_check.sh"
 
 source "run_coding_standards_check.sh"