tests: remove jsonschema from xenial tox environment.

Ubuntu 16.04 (xenial) does not have jsonschema installed by default.  As
it is listed in requirements, the tox environment will always have it
installed.

Add the helper tools/pipremove that removes pip packages.  Then use that
to remove jsonschema without noise of always running and ignoring a
'pip uninstall jsonschema'.

1 files changed, 14 insertions, 0 deletions

diff --git a/tools/pipremove b/tools/pipremove
new file mode 100755
index 00000000..f8f4ff11
--- /dev/null
+++ b/tools/pipremove
@@ -0,0 +1,14 @@
+#!/usr/bin/python3
+import subprocess
+import sys
+
+for pkg in sys.argv[1:]:
+    try:
+        exec('import %s' % pkg)  # pylint: disable=W0122
+    except ImportError:
+        continue
+    sys.stderr.write("%s removing package %s\n" % (sys.argv[0], pkg))
+    ret = subprocess.Popen(['pip', 'uninstall', '--yes', pkg]).wait()
+    if ret != 0:
+        sys.stderr.write("Failed to uninstall %s (%d)\n" % (pkg, ret))
+        sys.exit(ret)