Run demo scripts and check that they work

run_demos.py is the frontend to a framework for smoke-testing the
sample programs. It runs scripts called programs/*/*_demo.sh
("demo scripts") and check that they succeed. A typical demo script
runs one sample program or a combination of sample programs to
demonstrate their usage.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/run_demos.py b/tests/scripts/run_demos.py
new file mode 100755
index 0000000..3d4b1e0
--- /dev/null
+++ b/tests/scripts/run_demos.py
@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+"""Run the Mbed TLS demo scripts.
+"""
+import glob
+import subprocess
+import sys
+
+def run_demo(demo):
+    """Run the specified demo script. Return True if it succeeds."""
+    returncode = subprocess.call([demo])
+    return returncode == 0
+
+def run_demos(demos):
+    """Run the specified demos and print summary information about failures.
+
+    Return True if all demos passed and False if a demo fails.
+    """
+    failures = []
+    for demo in demos:
+        print('#### {} ####'.format(demo))
+        if not run_demo(demo):
+            failures.append(demo)
+            print('{}: FAIL'.format(demo))
+        print('')
+    successes = len(demos) - len(failures)
+    print('{}/{} demos passed'.format(successes, len(demos)))
+    if failures:
+        print('Failures:', *failures)
+    return not failures
+
+def run_all_demos():
+    """Run all the available demos.
+
+    Return True if all demos passed and False if a demo fails.
+    """
+    all_demos = glob.glob('programs/*/*_demo.sh')
+    return run_demos(all_demos)
+
+if __name__ == '__main__':
+    if not run_all_demos():
+        sys.exit(1)