test: check for error on invalid signal

Asserts that an error should be thrown when
an invalid signal is passed to process.kill().

PR-URL: nodejs#10026
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/parallel/test-process-kill-pid.js

@@ -24,6 +24,10 @@ assert.throws(function() { process.kill(+'not a number'); }, TypeError);
 assert.throws(function() { process.kill(1 / 0); }, TypeError);
 assert.throws(function() { process.kill(-1 / 0); }, TypeError);
 
+// Test that kill throws an error for invalid signal
+
+assert.throws(function() { process.kill(1, 'test'); }, Error);
+
 // Test kill argument processing in valid cases.
 //
 // Monkey patch _kill so that we don't actually send any signals, particularly