api tests: pick python3 if available

diff --git a/regression-tests.api/runtests b/regression-tests.api/runtests
index 47f25f0f12c6a0838980bb8836613f1c5b435622..dac34dd10d5385c337bfd851518b07b9abdf258d 100755 (executable)
--- a/regression-tests.api/runtests
+++ b/regression-tests.api/runtests
@@ -1,9 +1,17 @@
 #!/usr/bin/env bash
 
-PYTHON=${PYTHON:-python2}
-
 if [ ! -d .venv ]; then
-       virtualenv -p ${PYTHON} .venv
+  if [ -z "$PYTHON" ]; then
+    if [ ! -z "$(python3 --version | egrep '^Python 3.[6789]' 2>/dev/null)" ]; then
+      # found python3.6 or better
+      PYTHON=python3
+    else
+      # until we have better Linux distribution detection.
+      PYTHON=python2
+    fi
+  fi
+
+  virtualenv -p ${PYTHON} .venv
 fi
 . .venv/bin/activate
 python -V