add a test to validate sql.go matches goyacc output

Add a test script that regenerates the contents of sql.go into a temp
file and then compares to the current contents in order to make sure
that the version checked in matches the output of the expected
toolchain.

test/config.json

@@ -210,6 +210,17 @@
 				"site_test"
 			]
 		},
+		"parser_generator": {
+			"File": "",
+			"Args": [],
+			"Command": [
+				"tools/test_parser_generator.sh"
+			],
+			"Manual": false,
+			"Shard": 0,
+			"RetryMax": 0,
+			"Tags": []
+		},
 		"php": {
 			"File": "",
 			"Args": [],

tools/test_parser_generator.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+#
+# Validate that the current version of the generated parser matches the output
+# generated by the version of goyacc installed on the local system.
+#
+# This is used in travis to verify that the currently committed version was
+# generated with the proper version of goyacc.
+
+CUR="sql.go"
+TMP="/tmp/sql.$$.go"
+
+cd go/vt/sqlparser/
+
+goyacc -o $TMP sql.y
+gofmt -w $TMP
+
+diff -q $CUR $TMP > /dev/null 2>&1
+
+if [ $? != 0 ] ; then
+        echo "ERROR: Regenerated parser $TMP does not match current version `pwd`/sql.go:"
+        diff -u $CUR $TMP
+        exit 1
+fi
+
+rm $TMP