Always install a valid version of phpunit (#306)

.travis.yml

@@ -9,7 +9,8 @@ dist: xenial
 language: php
 
 php:
-  - '7.2'
+  - "7.2"
+  - "7.0"
 
 services:
   - mysql

scripts/check-diff.sh

@@ -6,8 +6,19 @@ function realpath {
 	php -r 'echo realpath( $argv[1] );' "$1"
 }
 
+# Return true (exit code 0) if the installed version of PHP is at least the reference.
+function php_is_atleast () {
+	php -r 'if ( ! version_compare( phpversion(), $argv[1], ">=" ) ) { exit( 1 ); }' "$1"
+}
+
+# Return true (exit code 0) if the installed version of PHP is above the reference.
+function php_is_above () {
+	php -r 'if ( ! version_compare( phpversion(), $argv[1], ">" ) ) { exit( 1 ); }' "$1"
+}
+
+# Deprecated: same as php_is_above.
 function min_php_version () {
-	php -r 'if ( version_compare( phpversion(), $argv[1], "<" ) ) { exit( 1 ); }' "$1"
+	php_is_above "$1"
 }
 
 function upsearch {
@@ -394,9 +405,9 @@ function download {
 
 function can_generate_coverage_clover {
 	if [ -e .coveralls.yml ] && [ -e composer.json ] && check_should_execute 'coverage'; then
-		if min_php_version "5.5.0" && cat composer.json | grep -Eq '"php-coveralls/php-coveralls"\s*:\s*"([(\^|~)]*(2|1.1)[0-9.]*|dev-master)"'; then
+		if php_is_above "5.5.0" && cat composer.json | grep -Eq '"php-coveralls/php-coveralls"\s*:\s*"([(\^|~)]*(2|1.1)[0-9.]*|dev-master)"'; then
 			return 0
-		elif min_php_version "5.3.3" && cat composer.json | grep -Eq '"php-coveralls/php-coveralls"\s*:\s*"[(\^|~)]*[0-9.]*"'; then
+		elif php_is_above "5.3.3" && cat composer.json | grep -Eq '"php-coveralls/php-coveralls"\s*:\s*"[(\^|~)]*[0-9.]*"'; then
 			return 0
 		fi
 	fi
@@ -414,13 +425,13 @@ function install_tools {
 	mkdir -p "$TEMP_TOOL_PATH"
 	PATH="$TEMP_TOOL_PATH:$PATH"
 
-	if ! min_php_version "5.3.0" && check_should_execute 'composer'; then
+	if ! php_is_above "5.3.0" && check_should_execute 'composer'; then
 		pecl install phar
 		DEV_LIB_SKIP="$DEV_LIB_SKIP,composer"
 	fi
 
 	# Skip installing Composer when the PHP version does not meet the php-coveralls package requirements.
-	if ! min_php_version "5.5.0" && [ -e composer.json ] && check_should_execute 'composer' && cat composer.json | grep -Eq '"satooshi/php-coveralls"\s*:\s*"dev-master"'; then
+	if ! php_is_above "5.5.0" && [ -e composer.json ] && check_should_execute 'composer' && cat composer.json | grep -Eq '"satooshi/php-coveralls"\s*:\s*"dev-master"'; then
 		DEV_LIB_SKIP="$DEV_LIB_SKIP,composer"
 	fi
 
@@ -451,16 +462,18 @@ function install_tools {
 
 	# Install PHP tools.
 	if [ -s "$TEMP_DIRECTORY/paths-scope-php" ]; then
-		if check_should_execute 'phpunit' && ! command -v phpunit >/dev/null 2>&1; then
+		# Ensure a valid version of phpunit exists. Versions installed with Composer
+		# will be loaded first because of the directory order in $PATH defined above.
+		if check_should_execute 'phpunit'; then
 			if [ -z "$PHPUNIT_VERSION" ]; then
-				if ! min_php_version "7.1"; then
+				PHPUNIT_VERSION="4"
+
+				if php_is_atleast "7.1"; then
 					PHPUNIT_VERSION="7"
-				elif ! min_php_version "7.0"; then
+				elif php_is_atleast "7.0"; then
 					PHPUNIT_VERSION="6"
-				elif ! min_php_version "5.6"; then
+				elif php_is_atleast "5.6"; then
 					PHPUNIT_VERSION="5"
-				else
-					PHPUNIT_VERSION="4"
 				fi
 			fi