diff --git a/.azure-pipelines.yml b/.azure-pipelines.yml
index e1e69c1aaf..8f9580bddd 100644
--- a/.azure-pipelines.yml
+++ b/.azure-pipelines.yml
@@ -276,7 +276,8 @@ jobs:
           pip install -r test/py/requirements.txt
           export PATH=/opt/qemu/bin:/tmp/uboot-test-hooks/bin:${PATH};
           export PYTHONPATH=/tmp/uboot-test-hooks/py/travis-ci;
-          ./test/py/test.py --bd ${TEST_PY_BD} ${TEST_PY_ID} -k "${TEST_PY_TEST_SPEC:-not a_test_which_does_not_exist}" --build-dir "$UBOOT_TRAVIS_BUILD_DIR";
+          # "${var:+"-k $var"}" expands to "" if $var is empty, "-k $var" if not
+          ./test/py/test.py --bd ${TEST_PY_BD} ${TEST_PY_ID} ${TEST_PY_TEST_SPEC:+"-k ${TEST_PY_TEST_SPEC}"} --build-dir "$UBOOT_TRAVIS_BUILD_DIR";
           ret=$?;
           if [[ $ret -ne 0 ]]; then
               exit $ret;
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2e77db777d..bf207db09e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -47,17 +47,14 @@ stages:
            --board ${TEST_PY_BD};
         exit $ret;
       fi
-    # "not a_test_which_does_not_exist" is a dummy -k parameter which will
-    # never prevent any test from running. That way, we can always pass
-    # "-k something" even when $TEST_PY_TEST_SPEC doesnt need a custom
-    # value.
     - virtualenv -p /usr/bin/python3 /tmp/venv
     - . /tmp/venv/bin/activate
     - pip install -r test/py/requirements.txt
+    # "${var:+"-k $var"}" expands to "" if $var is empty, "-k $var" if not
     - export PATH=/opt/qemu/bin:/tmp/uboot-test-hooks/bin:${PATH};
       export PYTHONPATH=/tmp/uboot-test-hooks/py/travis-ci;
       ./test/py/test.py --bd ${TEST_PY_BD} ${TEST_PY_ID}
-        -k "${TEST_PY_TEST_SPEC:-not a_test_which_does_not_exist}"
+        ${TEST_PY_TEST_SPEC:+"-k ${TEST_PY_TEST_SPEC}"}
         --build-dir "$UBOOT_TRAVIS_BUILD_DIR";
       ret=$?;
       if [[ $ret -ne 0 ]]; then
diff --git a/.travis.yml b/.travis.yml
index 43a0b7bb6c..c19eadd139 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -215,11 +215,8 @@ script:
        exit $ret;
      fi;
    fi
- # "not a_test_which_does_not_exist" is a dummy -k parameter which will
- # never prevent any test from running. That way, we can always pass
- # "-k something" even when $TEST_PY_TEST_SPEC doesnt need a custom
- # value.
  # Build just the one board needed for testing, if TEST_PY_BD is non-empty
+ # Note: "${var:+"-k $var"}" expands to "" if $var is empty, "-k $var" if not
  - if [[ "${TEST_PY_BD}" != "" ]]; then
      export UBOOT_TRAVIS_BUILD_DIR=`cd .. && pwd`/${TEST_PY_BD};
      cp ~/grub_x86.efi $UBOOT_TRAVIS_BUILD_DIR/;
@@ -248,7 +245,7 @@ script:
      . /tmp/venv/bin/activate;
      pip install -r test/py/requirements.txt;
      ./test/py/test.py --bd ${TEST_PY_BD} ${TEST_PY_ID}
-       -k "${TEST_PY_TEST_SPEC:-not a_test_which_does_not_exist}"
+       ${TEST_PY_TEST_SPEC:+"-k ${TEST_PY_TEST_SPEC}"}
        --build-dir "$UBOOT_TRAVIS_BUILD_DIR";
      ret=$?;
      if [[ $ret -ne 0 ]]; then