BUG19225481: Fix floating point inaccuracy with Python v2

Fix Connector/Python truncating digits from float values with
Python v2. This was not happening with Python v3 since str()
function in v3 does not truncate digits while converting
floats to string. This was resolved by using repr() instead of
str() for floating point values while converting them to string.

A unit test has been added for BUG19225481.

Author: peeyushgupta

lib/mysql/connector/conversion.py

@@ -138,7 +138,10 @@ def quote(self, buf):
         """
         if isinstance(buf, NUMERIC_TYPES):
             if PY2:
-                return str(buf)
+                if isinstance(buf, float):
+                    return repr(buf)
+                else:
+                    return str(buf)
             else:
                 return str(buf).encode('ascii')
         elif isinstance(buf, type(None)):

tests/test_bugs.py

@@ -2640,3 +2640,41 @@ def test_linestring(self):
         cur.execute('DROP TABLE IF EXISTS BugOra19164627')
         cur.close()
         cnx.close()
+
+
+class BugOra19225481(tests.MySQLConnectorTests):
+    """BUG#19225481: FLOATING POINT INACCURACY WITH PYTHON v2
+    """
+    def setUp(self):
+        config = tests.get_mysql_config()
+        self.cnx = connection.MySQLConnection(**config)
+        self.cursor = self.cnx.cursor()
+
+        self.tbl = 'Bug19225481'
+        self.cursor.execute("DROP TABLE IF EXISTS %s" % self.tbl)
+
+        create = 'CREATE TABLE {0}(col1 DOUBLE)'.format(
+            self.tbl)
+
+        self.cursor.execute(create)
+
+    def tearDown(self):
+        self.cursor.execute("DROP TABLE IF EXISTS %s" % self.tbl)
+        self.cursor.close()
+        self.cnx.close()
+
+    def test_columns(self):
+        values = [
+            (123.123456789987,),
+            (234.234,),
+            (12.12,),
+            (111.331,),
+            (0.0,),
+            (-99.99999900099,)
+        ]
+        stmt = "INSERT INTO {0} VALUES(%s)".format(self.tbl)
+        self.cursor.executemany(stmt, values)
+
+        stmt = "SELECT * FROM {0}".format(self.tbl)
+        self.cursor.execute(stmt)
+        self.assertEqual(values, self.cursor.fetchall())