Tests: added file descriptor to heredocs test for clarity and to test its functionality

Author: sebastian-echeverria

parse_test.go

@@ -118,7 +118,7 @@ func TestParseFile(t *testing.T) {
 }
 
 func TestParseReaderHeredocs(t *testing.T) {
-	dockerfile := `RUN <<EOF
+	dockerfile := `RUN 3<<EOF
 source $HOME/.bashrc && echo $HOME
 echo "Hello" >> /hello
 echo "World!" >> /hello
@@ -137,7 +137,7 @@ EOF
 			Heredocs: []Heredoc{
 				Heredoc{
 					Name:           "EOF",
-					FileDescriptor: 0,
+					FileDescriptor: 3,
 					Content:        "source $HOME/.bashrc && echo $HOME\necho \"Hello\" >> /hello\necho \"World!\" >> /hello\n"},
 			},
 		},

tests/dockerfile_test.py

@@ -115,7 +115,7 @@ def test_parse_file_success():
 
 def test_heredoc_string_success():
     test_string = (
-        'RUN <<EOF\n'
+        'RUN 3<<EOF\n'
         'source $HOME/.bashrc && echo $HOME\n'
         'echo "Hello" >> /hello\n'
         'echo "World!" >> /hello\n'
@@ -137,7 +137,7 @@ def test_heredoc_string_success():
                     content='source $HOME/.bashrc && echo $HOME\n'
                             'echo "Hello" >> /hello\n'
                             'echo "World!" >> /hello\n',
-                    file_descriptor=0,
+                    file_descriptor=3,
                 ),
             ),
         ),