Updated Ruby matrix and handle TinyTDS false result

Author: aidanharan

appveyor.yml

@@ -34,9 +34,9 @@ environment:
   CI_AZURE_PASS:
     secure: cSQp8sk4urJYvq0utpsK+r7J+snJ2wpcdp8RdXJfB+w=
   matrix:
+#   - ruby_version: "25"     # Fails because of "File does not exist: tiny_tds/tiny_tds" error (See https://github.com/rails-sqlserver/tiny_tds/issues/391).
     - ruby_version: "25-x64"
-    - ruby_version: "25"
+#   - ruby_version: "26"     # Fails because of "File does not exist: tiny_tds/tiny_tds" error (See https://github.com/rails-sqlserver/tiny_tds/issues/391).
     - ruby_version: "26-x64"
-    - ruby_version: "26"
-    - ruby_version: "27-x64"
-    - ruby_version: "27"
+#   - ruby_version: "27"     # Ruby version not installed on AppVeyor Windows instance.
+#   - ruby_version: "27-x64" # Ruby version not installed on AppVeyor Windows instance.

lib/active_record/connection_adapters/sqlserver/database_statements.rb

@@ -351,7 +351,10 @@ def raw_connection_do(sql)
           case @connection_options[:mode]
           when :dblib
             result = @connection.execute(sql)
-            raise ActiveRecordError, 'Database connection has failed' if result == false
+            # If connection fails then TinyTDS returns false instead of an exception (see https://github.com/rails-sqlserver/tiny_tds/issues/464)
+            if result == false
+              raise TinyTds::Error, 'TinyTDS execute returned false instead of results'
+            end
             result.do
           end
         ensure