diff --git a/tests/ci.sh b/tests/ci.sh
index 113beda..cbeb344 100755
--- a/tests/ci.sh
+++ b/tests/ci.sh
@@ -1,12 +1,18 @@
 set -x
 
+composer self-update
+composer install --prefer-source --no-interaction
+
+# Use composer's phpunit and phpcs by adding composer bin directory to the path environment variable.
+export PATH="${PWD}/vendor/bin:${PATH}"
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+cd "${SCRIPT_DIR}"
+
 echo "CI_PHP_VERSION: ${CI_PHP_VERSION}"
 php -r "var_dump(phpversion());"
 php -r "var_dump(curl_version());"
 
-composer self-update
-composer install --prefer-source --no-interaction
-
 # Let test server know we should allow testing.
 export PHP_CURL_CLASS_TEST_MODE_ENABLED="yes"
 
@@ -17,15 +23,9 @@ for i in $(seq 0 $(("${server_count}" - 1))); do
     port=8000
     (( port += $i ))
 
-    php -S "127.0.0.1:${port}" -t tests/PHPCurlClass/ &
+    php -S "127.0.0.1:${port}" -t PHPCurlClass/ &
 done
 
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-cd "${SCRIPT_DIR}"
-
-# Use composer's phpunit and phpcs by adding composer bin directory to the path environment variable.
-export PATH="${PWD}/vendor/bin:${PATH}"
-
 remove_expectWarning() {
     # Fix "Call to undefined method CurlTest\CurlTest::expectWarning()".
     sed -i'' -e"/->expectWarning(/d" "./PHPCurlClass/PHP"*
@@ -64,7 +64,7 @@ else
 fi
 
 phpunit_version="$("${phpunit_to_use}" --version | grep -Eo "[0-9]+\.[0-9]+\.[0-9]+")"
-echo "${phpunit_version}"
+echo "phpunit_version: ${phpunit_version}"
 
 if [[ "${phpunit_version}" == "6.5."* ]]; then
     phpunit_v6_5_shim
@@ -76,7 +76,10 @@ fi
 
 # Run tests.
 "${phpunit_to_use}" --version
-"${phpunit_to_use}" --configuration "phpunit.xml" --debug --verbose
+"${phpunit_to_use}" \
+    --configuration "phpunit.xml" \
+    --debug \
+    --verbose
 if [[ "${?}" -ne 0 ]]; then
     echo "Error: phpunit command failed"
     errors+=("phpunit command failed")
@@ -84,6 +87,8 @@ fi
 
 source "check_coding_standards.sh"
 
+set +x
+
 error_count="${#errors[@]}"
 if [[ "${error_count}" -ge 1 ]]; then
     echo -e "\nErrors found: ${error_count}"
@@ -96,4 +101,9 @@ if [[ "${error_count}" -ge 1 ]]; then
     done
 fi
 
+# Stop test servers.
+for pid in "${pids[@]}"; do
+  kill "${pid}" &> /dev/null &
+done
+
 exit "${#errors[@]}"
diff --git a/tests/run.sh b/tests/run.sh
index dcac8aa..16a9bec 100755
--- a/tests/run.sh
+++ b/tests/run.sh
@@ -1,7 +1,14 @@
+set -x
+
+# Use composer's phpunit and phpcs by adding composer bin directory to the path environment variable.
+export PATH="${PWD}/vendor/bin:${PATH}"
+
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 cd "${SCRIPT_DIR}"
 
-set -x
+echo "CI_PHP_VERSION: ${CI_PHP_VERSION}"
+php -r "var_dump(phpversion());"
+php -r "var_dump(curl_version());"
 
 # Let test server know we should allow testing.
 export PHP_CURL_CLASS_TEST_MODE_ENABLED="yes"
@@ -15,27 +22,89 @@ for i in $(seq 0 $(("${server_count}" - 1))); do
     (( port += $i ))
 
     php -S "127.0.0.1:${port}" -t PHPCurlClass/ &> /dev/null &
-    pid="${!}"
-
-    pids["${i}"]="${pid}"
+    pids["${i}"]="${!}"
 done
 
+remove_expectWarning() {
+    # Fix "Call to undefined method CurlTest\CurlTest::expectWarning()".
+    sed -i'' -e"/->expectWarning(/d" "./PHPCurlClass/PHP"*
+}
+
+replace_assertStringContainsString() {
+    # -->assertStringContainsString(
+    # +->assertContains(
+    find='->assertStringContainsString('
+    replace='->assertContains('
+    sed -i'' -e"s/${find}/${replace}/" "./PHPCurlClass/PHP"*
+}
+
+phpunit_v6_5_shim() {
+    remove_expectWarning
+    replace_assertStringContainsString
+}
+
+phpunit_v7_5_shim() {
+    remove_expectWarning
+}
+
+phpunit_v8_1_shim() {
+    remove_expectWarning
+}
+
+errors=()
+
+source "check_syntax.sh"
+
 # Determine which phpunit to use.
-if [[ -f "../vendor/phpunit/phpunit/phpunit" ]]; then
-    phpunit_to_use="../vendor/phpunit/phpunit/phpunit"
+if [[ -f "../vendor/bin/phpunit" ]]; then
+    phpunit_to_use="../vendor/bin/phpunit"
 else
     phpunit_to_use="phpunit"
 fi
 
+phpunit_version="$("${phpunit_to_use}" --version | grep -Eo "[0-9]+\.[0-9]+\.[0-9]+")"
+echo "phpunit_version: ${phpunit_version}"
+
+if [[ "${phpunit_version}" == "6.5."* ]]; then
+    phpunit_v6_5_shim
+elif [[ "${phpunit_version}" == "7.5."* ]]; then
+    phpunit_v7_5_shim
+elif [[ "${phpunit_version}" == "8.1."* ]]; then
+    phpunit_v8_1_shim
+fi
+
 # Run tests.
 extra_args="${@}"
+"${phpunit_to_use}" --version
 "${phpunit_to_use}" \
     --configuration "phpunit.xml" \
     --debug \
     --verbose \
     ${extra_args}
+if [[ "${?}" -ne 0 ]]; then
+    echo "Error: phpunit command failed"
+    errors+=("phpunit command failed")
+fi
+
+source "check_coding_standards.sh"
+
+set +x
+
+error_count="${#errors[@]}"
+if [[ "${error_count}" -ge 1 ]]; then
+    echo -e "\nErrors found: ${error_count}"
+
+    iter=0
+    for value in "${errors[@]}"; do
+        ((iter++))
+        echo -e "\nError ${iter} of ${error_count}:"
+        echo "${value}" | perl -pe 's/^(.*)$/\t\1/'
+    done
+fi
 
 # Stop test servers.
 for pid in "${pids[@]}"; do
-  kill "${pid}"
+  kill "${pid}" &> /dev/null &
 done
+
+exit "${#errors[@]}"