AVR: Add expect script to run test in simavr and check for success.

ports/avr/run_test.exp

@@ -0,0 +1,31 @@
+#!/usr/bin/env expect
+
+# Start the test (arguments: <path_to_simavr> <cpu_part> <test_elf_file>)
+spawn [lindex $argv 0] -m [lindex $argv 1] [lindex $argv 2]
+
+# Expect to see the test starting within 10 seconds
+set timeout 10
+
+# Wait for the test to start ("Go..")
+expect {
+	"Go.." {
+		puts "Test started"
+
+		# The test could take up to 3 minutes to complete once started
+		set timeout 180
+
+		# Now expect to see "Pass.." or "Fail" within 3 minutes
+		expect {
+			"Pass.." { puts "Test passed"; exit 0 }
+			"Fail" { puts "Test failed"; exit 1 }
+			timeout { puts "Test timed out without completing"; exit 1 }
+		}
+	}
+
+	timeout {
+		# Didn't receive "Go.." within 10 seconds
+		puts "Test failed to start ('Go' not seen)"
+		exit 1
+	}
+}
+