diff --git a/tests/test.sh b/tests/test.sh
index bd25f60..4843c1c 100644
--- a/tests/test.sh
+++ b/tests/test.sh
@@ -7,6 +7,7 @@ ERROR_NUM=0
 DATA_DIR="$(pwd)/tests/fixtures/source/bitwarden/data"
 OUTPUT_DIR="output"
 EXTRACT_DIR="extract"
+TEMP_DIR="tmp"
 REMOTE_DIR="/${OUTPUT_DIR}"
 
 ########################################
@@ -86,6 +87,7 @@ function test_result() {
     color red "Test case \"$1\" failed"
 }
 
+. tests/units/env-priority/test.sh
 . tests/units/backup-zip-file/test.sh
 . tests/units/backup-7z-file/test.sh
 . tests/units/backup-unpackage/test.sh
diff --git a/tests/units/env-priority/test.sh b/tests/units/env-priority/test.sh
new file mode 100644
index 0000000..c12c61f
--- /dev/null
+++ b/tests/units/env-priority/test.sh
@@ -0,0 +1,134 @@
+#!/bin/bash
+
+TEST_NAME="env-priority"
+TEST_OUTPUT_DIR="$(pwd)/${OUTPUT_DIR}/${TEST_NAME}"
+TEST_TEMP_DIR="$(pwd)/${TEMP_DIR}/${TEST_NAME}"
+
+PASSWORD1="32aeec18-3bce-43af-b41d-7be04b0f7810" # For 1
+PASSWORD2="ce3cbc42-186b-4d1b-a1a9-3f10f0ec59c7" # For 2
+PASSWORD3="0e0fdbc1-5b2f-44db-ac7d-f0a8764992a7" # For 3
+PASSWORD4="0ddd9b27-ca9b-4912-b6fb-76569ec5cac1" # For 4
+PASSWORD2_FILE="${TEST_TEMP_DIR}/password2"
+PASSWORD3_FILE="${TEST_TEMP_DIR}/password3"
+BACKUP_FILE1="${TEST_OUTPUT_DIR}/backup.test1.zip"
+BACKUP_FILE2="${TEST_OUTPUT_DIR}/backup.test2.zip"
+BACKUP_FILE3="${TEST_OUTPUT_DIR}/backup.test3.zip"
+BACKUP_FILE4="${TEST_OUTPUT_DIR}/backup.test4.zip"
+ENV_FILE1="${TEST_TEMP_DIR}/.env1"
+ENV_FILE4="${TEST_TEMP_DIR}/.env4"
+
+FAILED_NUM=0
+
+color yellow "Starting test case \"${TEST_NAME}\""
+
+function prepare() {
+    mkdir -p "${TEST_OUTPUT_DIR}" "${TEST_TEMP_DIR}"
+
+    echo "${PASSWORD2}" > "${PASSWORD2_FILE}"
+    echo "${PASSWORD3}" > "${PASSWORD3_FILE}"
+
+    cat > "${ENV_FILE1}" << EOF
+ZIP_PASSWORD_FILE: "/password3"
+ZIP_PASSWORD: "${PASSWORD4}"
+EOF
+    cat > "${ENV_FILE4}" << EOF
+ZIP_PASSWORD: "${PASSWORD4}"
+EOF
+}
+
+function start() {
+    docker run --rm \
+        --mount "type=bind,source=${TEST_OUTPUT_DIR},target=${REMOTE_DIR}" \
+        --mount "type=bind,source=${PASSWORD2_FILE},target=/password2" \
+        --mount "type=bind,source=${PASSWORD3_FILE},target=/password3" \
+        --mount "type=bind,source=${ENV_FILE1},target=/.env" \
+        -e "RCLONE_REMOTE_DIR=${REMOTE_DIR}" \
+        -e "ZIP_PASSWORD=${PASSWORD1}" \
+        -e "ZIP_PASSWORD_FILE=/password2" \
+        -e "BACKUP_FILE_SUFFIX=test1" \
+        "${DOCKER_IMAGE}" \
+        backup
+
+    docker run --rm \
+        --mount "type=bind,source=${TEST_OUTPUT_DIR},target=${REMOTE_DIR}" \
+        --mount "type=bind,source=${PASSWORD2_FILE},target=/password2" \
+        --mount "type=bind,source=${PASSWORD3_FILE},target=/password3" \
+        --mount "type=bind,source=${ENV_FILE1},target=/.env" \
+        -e "RCLONE_REMOTE_DIR=${REMOTE_DIR}" \
+        -e "ZIP_PASSWORD_FILE=/password2" \
+        -e "BACKUP_FILE_SUFFIX=test2" \
+        "${DOCKER_IMAGE}" \
+        backup
+
+    docker run --rm \
+        --mount "type=bind,source=${TEST_OUTPUT_DIR},target=${REMOTE_DIR}" \
+        --mount "type=bind,source=${PASSWORD2_FILE},target=/password2" \
+        --mount "type=bind,source=${PASSWORD3_FILE},target=/password3" \
+        --mount "type=bind,source=${ENV_FILE1},target=/.env" \
+        -e "RCLONE_REMOTE_DIR=${REMOTE_DIR}" \
+        -e "BACKUP_FILE_SUFFIX=test3" \
+        "${DOCKER_IMAGE}" \
+        backup
+
+    docker run --rm \
+        --mount "type=bind,source=${TEST_OUTPUT_DIR},target=${REMOTE_DIR}" \
+        --mount "type=bind,source=${PASSWORD2_FILE},target=/password2" \
+        --mount "type=bind,source=${PASSWORD3_FILE},target=/password3" \
+        --mount "type=bind,source=${ENV_FILE4},target=/.env" \
+        -e "RCLONE_REMOTE_DIR=${REMOTE_DIR}" \
+        -e "BACKUP_FILE_SUFFIX=test4" \
+        "${DOCKER_IMAGE}" \
+        backup
+}
+
+function test() {
+    color blue "Testing..."
+
+    ls -l "${TEST_OUTPUT_DIR}"
+
+    7z l -p"${PASSWORD1}" "${BACKUP_FILE1}"
+    if [[ $? != 0 ]]; then
+        ((FAILED_NUM++))
+    fi
+
+    7z l -p"${PASSWORD2}" "${BACKUP_FILE2}"
+    if [[ $? != 0 ]]; then
+        ((FAILED_NUM++))
+    fi
+
+    7z l -p"${PASSWORD3}" "${BACKUP_FILE3}"
+    if [[ $? != 0 ]]; then
+        ((FAILED_NUM++))
+    fi
+
+    7z l -p"${PASSWORD4}" "${BACKUP_FILE4}"
+    if [[ $? != 0 ]]; then
+        ((FAILED_NUM++))
+    fi
+}
+
+function cleanup() {
+    rm -rf "${TEST_OUTPUT_DIR}" "${TEST_TEMP_DIR}"
+
+    unset TEST_OUTPUT_DIR
+    unset TEST_TEMP_DIR
+    unset PASSWORD1
+    unset PASSWORD2
+    unset PASSWORD3
+    unset PASSWORD4
+    unset PASSWORD2_FILE
+    unset PASSWORD3_FILE
+    unset BACKUP_FILE1
+    unset BACKUP_FILE2
+    unset BACKUP_FILE3
+    unset BACKUP_FILE4
+    unset ENV_FILE1
+    unset ENV_FILE4
+}
+
+prepare
+start
+test
+cleanup
+
+test_result "${TEST_NAME}" "${FAILED_NUM}"