add bats test

examples/print/tests/basic.bats

@@ -0,0 +1,17 @@
+# Executed before each test.
+setup() {
+  cd examples/print
+  # Make sure the directory is clean.
+  dfx start --clean --background
+}
+
+# executed after each test
+teardown() {
+  dfx stop
+}
+
+@test "Can print" {
+  dfx deploy
+
+  dfx canister call print print
+}