check if ninja supported by cmake

01-basic/J-building-with-ninja/run_test.sh

@@ -1,2 +1,11 @@
+#!/bin/bash
+# Travis-ci cmake version doesn't support ninja, so first check if it's supported
+ninja_supported=`cmake --help | grep Ninja`
+
+if [ -z $ninja_supported ]; then
+    echo "Ninja not supported"
+    exit
+fi
+
 mkdir -p build.ninja && cd build.ninja && \
     cmake .. -G Ninja && ninja