tests: Check if test file is readable before running it

I tried calling this script with "tests/foo.lua" as an argument, but it actually
expects "foo.lua" since it changes into the appropriate directory itself.
Because this file does not exist, "cat $f | awesome-client" failed and thus this
whole script just hung (the test runner was never actually started).

Fix this by testing for the test-file to exist before trying to run it.

Signed-off-by: Uli Schlachter <psychon@znc.in>

tests/run.sh

@@ -126,6 +126,13 @@ errors=0
 
 for f in $tests; do
     echo "== Running $f =="
+
+    if [ ! -r $f ]; then
+        echo "===> ERROR $f is not readable! <==="
+        errors=$(expr $errors + 1)
+        continue
+    fi
+
     start_awesome
 
     # Send the test file to awesome.