test to reproduce behavior of issue brianc#549

a fix was provided in 5079c1e;
test is modeled on query-error-handling-tests.js;
test both kill query and disconnection on prepared statement execution;
make connection error string message consistent between native and non-native;
disable test server-side kill for native as it hangs;
sync can cause error to be emitted so we catch that;
we also move _ending state before _send is called.

Author: Ricky Ng-Adam

lib/client.js

@@ -176,13 +176,13 @@ Client.prototype.connect = function(callback) {
   con.once('end', function() {
     if ( callback ) {
       // haven't received a connection message yet !
-      var err = new Error("Stream unexpectedly ended before getting ready for query execution");
+      var err = new Error('Connection was ended during query');
       callback(err);
       callback = null;
       return;
     }
     if(self.activeQuery) {
-      var disconnectError = new Error('Stream unexpectedly ended during query execution');
+      var disconnectError = new Error('Connection was ended during query');
       self.activeQuery.handleError(disconnectError, con);
       self.activeQuery = null;
     }

lib/connection.js

@@ -285,14 +285,15 @@ Connection.prototype.sync = function() {
   this.writer.flush(0);
 
   this.writer.add(emptyBuffer);
+  this._ending = true;
   this._send(0x53);
 };
 
 Connection.prototype.end = function() {
   //0x58 = 'X'
   this.writer.add(emptyBuffer);
-  this._send(0x58);
   this._ending = true;
+  this._send(0x58);
 };
 
 Connection.prototype.describe = function(msg, more) {

test/integration/client/query-error-handling-prepared-statement-tests.js

@@ -0,0 +1,83 @@
+var helper = require(__dirname + '/test-helper');
+var util = require('util');
+
+function killIdleQuery(targetQuery) {
+  var client2 = new Client(helper.args);
+  var pidColName = 'procpid'
+  var queryColName = 'current_query';
+  client2.connect(assert.success(function() {
+    helper.versionGTE(client2, '9.2.0', assert.success(function(isGreater) {
+      if(isGreater) {
+        pidColName = 'pid';
+        queryColName = 'query';
+      }
+      var killIdleQuery = "SELECT " + pidColName + ", (SELECT pg_terminate_backend(" + pidColName + ")) AS killed FROM pg_stat_activity WHERE " + queryColName + " = $1";
+      client2.query(killIdleQuery, [targetQuery], assert.calls(function(err, res) {
+        assert.ifError(err);
+        assert.equal(res.rows.length, 1);
+        client2.end();
+        assert.emits(client2, 'end');
+      }));
+    }));
+  }));
+}
+
+test('query killed during query execution of prepared statement', function() {
+  if(helper.args.native) {
+    return false;
+  }
+  var client = new Client(helper.args);
+  client.connect(assert.success(function() {
+    var sleepQuery = 'select pg_sleep($1)';
+    var query1 = client.query({
+      name: 'sleep query',
+      text: sleepQuery,
+      values: [5] },
+      assert.calls(function(err, result) {
+        assert.equal(err.message, 'terminating connection due to administrator command');
+    }));
+
+    query1.on('error', function(err) {
+      assert.fail('Prepared statement should not emit error');
+    });
+
+    query1.on('row', function(row) {
+      assert.fail('Prepared statement should not emit row');
+    });
+
+    query1.on('end', function(err) {
+      assert.fail('Prepared statement when executed should not return before being killed');
+    });
+
+    killIdleQuery(sleepQuery);
+  }));
+});
+
+
+test('client end during query execution of prepared statement', function() {
+  var client = new Client(helper.args);
+  client.connect(assert.success(function() {
+    var sleepQuery = 'select pg_sleep($1)';
+    var query1 = client.query({
+      name: 'sleep query',
+      text: sleepQuery,
+      values: [5] },
+      assert.calls(function(err, result) {
+        assert.equal(err.message, 'Connection was ended during query');
+    }));
+
+    query1.on('error', function(err) {
+      assert.fail('Prepared statement should not emit error');
+    });
+
+    query1.on('row', function(row) {
+      assert.fail('Prepared statement should not emit row');
+    });
+
+    query1.on('end', function(err) {
+      assert.fail('Prepared statement when executed should not return before being killed');
+    });
+
+    client.end();
+  }));
+});