diff --git a/tests/test_expand_pg_ldap_sync.bats b/tests/test_expand_pg_ldap_sync.bats
new file mode 100644
index 0000000..2921150
--- /dev/null
+++ b/tests/test_expand_pg_ldap_sync.bats
@@ -0,0 +1,180 @@
+# bats file_tags=ruby:expand_pg_ldap_sync
+
+setup() {
+    touch test_output.yaml
+    # get the containing directory of this file using $BATS_TEST_FILENAME
+    # instead of ${BASH_SOURCE[0]} or $0, as those will point to the bats
+    # executable's location or the preprocessed file respectively
+    TEST_DIR="$(cd "$(dirname "$BATS_TEST_FILENAME")" >/dev/null 2>&1 && pwd)"
+}
+
+
+check_success() {
+  if (( status )); then
+    echo $output
+    return 1
+  fi
+}
+
+check_failure() {
+  if (( ! status )); then
+    echo $output
+    return 1
+  fi
+}
+
+test_expansion() {
+    rm test_output.yaml
+    ${TEST_DIR}/../scripts/expand_pg_ldap_sync.rb > test_output.yaml
+    grep "$1" test_output.yaml && return
+    echo "Failed to find '$1' in expanded output"
+    cat test_output.yaml
+    return 1
+}
+
+@test "Test setting LDAP_BIND_DN" {
+  export LDAP_BIND_DN="CN=user,DC=example,DC=com"
+  run test_expansion 'username: "CN=user,DC=example,DC=com"'
+  export -n LDAP_BIND_DN
+  check_success
+}
+
+@test "Test setting LDAP_BIND_PASSWORD only" {
+  export LDAP_BIND_PASSWORD="!a#b$c"
+  run test_expansion 'password: "!a#b$c"'
+  export -n LDAP_BIND_PASSWORD
+  check_failure
+}
+
+@test "Test setting LDAP_BIND_PASSWORD with LDAP_BIND_DN" {
+  export LDAP_BIND_DN="CN=user,DC=example,DC=com"
+  export LDAP_BIND_PASSWORD="!a#b%c"
+  run test_expansion 'password: "!a#b%c"'
+  export -n LDAP_BIND_DN LDAP_BIND_PASSWORD
+  check_success
+}
+
+@test "Test setting LDAP_GROUP_BASE_DN" {
+  export LDAP_GROUP_BASE_DN="OU=groups,DC=example,DC=com"
+  run test_expansion 'base: "OU=groups,DC=example,DC=com"'
+  export -n LDAP_GROUP_BASE_DN
+  check_success
+}
+
+@test "Test setting LDAP_GROUP_FILTER" {
+  export LDAP_GROUP_FILTER="(objectClass=posixGroup)"
+  run test_expansion 'filter: "(objectClass=posixGroup)"'
+  export -n LDAP_GROUP_FILTER
+  check_success
+}
+
+@test "Test setting LDAP_GROUP_NAME_ATTR" {
+  export LDAP_GROUP_NAME_ATTR="samAccountName"
+  run test_expansion 'name_attribute: "samAccountName"'
+  export -n LDAP_GROUP_NAME_ATTR
+  check_success
+}
+
+@test "Test default LDAP_GROUP_NAME_ATTR" {
+  export -n LDAP_GROUP_NAME_ATTR
+  run test_expansion 'name_attribute: "cn"'
+  check_success
+}
+
+@test "Test setting LDAP_HOST" {
+  export LDAP_HOST="ldap.example.com"
+  run test_expansion 'host: "ldap.example.com"'
+  export -n LDAP_HOST
+  check_success
+}
+
+@test "Test setting LDAP_PORT" {
+  export LDAP_PORT="1234"
+  run test_expansion 'port: "1234"'
+  export -n LDAP_PORT
+  check_success
+}
+
+@test "Test default LDAP_PORT" {
+  export -n LDAP_PORT
+  run test_expansion 'port: "389"'
+  check_success
+}
+
+@test "Test setting LDAP_USER_BASE_DN" {
+  export LDAP_USER_BASE_DN="OU=users,DC=example,DC=com"
+  run test_expansion 'base: "OU=users,DC=example,DC=com"'
+  export -n LDAP_USER_BASE_DN
+  check_success
+}
+
+@test "Test setting LDAP_USER_FILTER" {
+  export LDAP_USER_FILTER="(objectClass=posixAccount)"
+  run test_expansion 'filter: "(objectClass=posixAccount)"'
+  export -n LDAP_USER_FILTER
+  check_success
+}
+
+@test "Test setting LDAP_USER_NAME_ATTR" {
+  export LDAP_USER_NAME_ATTR="samAccountName"
+  run test_expansion 'name_attribute: "samAccountName"'
+  export -n LDAP_USER_NAME_ATTR
+  check_success
+}
+
+@test "Test default LDAP_USER_NAME_ATTR" {
+  export -n LDAP_USER_NAME_ATTR
+  run test_expansion 'name_attribute: "userPrincipalName"'
+  check_success
+}
+
+@test "Test setting POSTGRESQL_DB_NAME" {
+  export POSTGRESQL_DB_NAME="db-names"
+  run test_expansion 'dbname: "db-names"'
+  export -n POSTGRESQL_DB_NAME
+  check_success
+}
+
+@test "Test default POSTGRESQL_DB_NAME" {
+  export -n POSTGRESQL_DB_NAME
+  run test_expansion 'dbname: "guacamole"'
+  check_success
+}
+
+@test "Test setting POSTGRESQL_HOST" {
+  export POSTGRESQL_HOST="postgresql.example.com"
+  run test_expansion 'host: "postgresql.example.com"'
+  export -n POSTGRESQL_HOST
+  check_success
+}
+
+@test "Test setting POSTGRESQL_PASSWORD" {
+  export POSTGRESQL_PASSWORD="!a#b%c"
+  run test_expansion 'password: "!a#b%c"'
+  export -n POSTGRESQL_PASSWORD
+  check_success
+}
+
+@test "Test setting POSTGRESQL_PORT" {
+  export POSTGRESQL_PORT="1234"
+  run test_expansion 'port: "1234"'
+  export -n POSTGRESQL_PORT
+  check_success
+}
+
+@test "Test default POSTGRESQL_PORT" {
+  export -n POSTGRESQL_PORT
+  run test_expansion 'port: "5432"'
+  check_success
+}
+
+@test "Test setting POSTGRESQL_USERNAME" {
+  export POSTGRESQL_USERNAME="psqladmin"
+  run test_expansion 'user: "psqladmin"'
+  export -n POSTGRESQL_USERNAME
+  check_success
+}
+
+teardown() {
+  rm test_output.yaml
+}
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