question: public void test_ConstructorLjava_lang_StringLjava_text_DecimalFormatSymbols ( ) { try { DecimalFormatSymbols dfs = new DecimalFormatSymbols ( Locale . CANADA ) ; DecimalFormat format1 = new DecimalFormat ( "'$'1000.0000" , dfs ) ; DecimalFormat format2 = new DecimalFormat ( ) ; format2 . applyPattern ( "'$'1000.0000" ) ; format2 . setDecimalFormatSymbols ( dfs ) ; assertTrue ( "Constructed format did not match applied format object" , format2 . equals ( format1 ) ) ; assertTrue ( "Constructed format did not match applied format object" , ! format1 . equals ( new DecimalFormat ( "'$'1000.0000" , new DecimalFormatSymbols ( Locale . CHINA ) ) ) ) ; try { new DecimalFormat ( "'$'1000.0000" , ( DecimalFormatSymbols ) null ) ; fail ( "Expected NullPointerException was not thrown" ) ; } catch ( NullPointerException e ) { } try { new DecimalFormat ( null , new DecimalFormatSymbols ( ) ) ; fail ( "Expected NullPointerException was not thrown" ) ; } catch ( NullPointerException e ) { } try { new DecimalFormat ( null , ( DecimalFormatSymbols ) null ) ; fail ( "Expected NullPointerException was not thrown" ) ; } catch ( NullPointerException e ) { } try { new DecimalFormat ( "$'" , new DecimalFormatSymbols ( ) ) ; fail ( "Expected IllegalArgumentException was not thrown" ) ; } catch ( IllegalArgumentException e ) { } } catch ( Exception e ) { fail ( "Unexpected exception " + e . toString ( ) ) ; } }
target:  Case 1: Try to construct object using correct pattern and fromat symbols. Case 2: Try to construct object using null arguments. Case 3: Try to construct object using incorrect pattern.