evaluate invokes FracCalcOliver... Test Output->
but Fraction not yet returned.

-> Test output shows that some work needs to be done!

$ java -ea FractionCalculatorTest
FractionCalculator verbose output:
debug need to write mechanism to get Fraction back from FracCalcOliver
ERROR get FAIL for test "Coursework 2 sheet 'Extended example' table 1st line: '1/2 - 3/4 * abs ' should give Fraction.equals 1/4. ".

Now start test 'Entering two operations: ' 1 - - 1' should result in an appropriate error message an null Fraction'

ERROR you have input two operators: - and -.
	Resetting calculator to its initial state (no operator and 0 as value)
test "Entering two operations: ' 1 - - 1' should result in an appropriate error message an null Fraction" passes.

FractionCalculatorTest: 1 tests FAIL.
Exception in thread "main" java.lang.AssertionError: FractionCalculatorTest failed 1 tests
	at FractionCalculatorTest.simpleTests(FractionCalculatorTest.java:45)
	at FractionCalculatorTest.main(FractionCalculatorTest.java:11)
method getFraction()...         Example output ->
to provide access to the Fraction object now needed.

Example output of interactive calculator showing it still works:
(>>> is the user prompt).

$ java FracCalcOliver
Simple text-based calculator to compute with fractions.
author: Oliver S. Smart
0 >>> 2 * 3 + 1/2 neg /2

ERROR unrecognized input '/2' cannot process this
	Resetting calculator to its initial state (no operator and 0 as value)
0 >>> 2 * 3 + 1/2 neg / 2
-13/4 >>> + 1
-9/4 >>> abs
9/4 >>> quit
Goodbye
evaluate altered to object method... Test Output->
... because of Keith's instructions on moodle not to use System.exit
to quit but instead come up with a different way of letting
the caller know the instruction to quit.

FractionCalculatorTest now tests that evaluate works properly:

1 that the example input in table works as expected
2 that supply the result of the previous method routine as
  input to the next works fine
3 that entry of "quit" results in caller being able to detect this.
4 that supply an erroneous input results in a direct print
  out error message and indication to caller there is
  and error.

I am happy that the test results indicate we are ready for the
next stage: writing main.

-> Test output:
$ java -ea FractionCalculatorTest
FractionCalculator verbose output:
test "Coursework 2 sheet 'Extended example' table 1st line start from 0/1 '1/2 - 3/4 * abs ' should give Fraction.equals 1/4. " passes.

test "Test giving previous result as the input fraction '* 8 neg' should give Fraction.equals -2/1 " passes.

test "Test entry of quit in mixed case  '+ 4 abs qUiT  neg' should give .quitProgram()==true" passes.

Now start test 'Entering two operations: '1 - - 1' should result in...
 	 (a) foundError() providing true to caller
	 (b) direct print out of an appropriate error message. So the next message
	     should be an ERROR message! (This check must be by "eye".)'

ERROR you have input two operators: - and -.
	Resetting calculator to its initial state (no operator and 0 as value)
test "Entering two operations: '1 - - 1' foundError()==true" passes.

FractionCalculatorTest: All tests pass

$ java -ea FractionCalculatorTest
FractionCalculator verbose output:
test "Coursework 2 sheet 'Extended example' table 1st line: '1/2 - 3/4 * abs ' should give Fraction.equals 1/4. " passes.

Now start test 'Entering two operations: ' 1 - - 1' should result in...
 	 (a) foundError() providing true to caller
	 (a) direct print out of an appropriate error message. So the next message
	     should be an ERROR message! (Check must be by eye).
'

ERROR you have input two operators: - and -.
	Resetting calculator to its initial state (no operator and 0 as value)
test "Entering two operations: ' 1 - - 1' should result in...
 	 (a) foundError() providing true to caller
	 (a) direct print out of an appropriate error message. So the next message
	     should be an ERROR message! (Check must be by eye).
" passes.

FractionCalculatorTest: All tests pass
write "main" interactive...   Example Output->
... calculator (basic mode).

->Example Output for a test using Coursework sheet table
entries, followed by demonstration that result is
carried over, a divide by zero test of error
handling:

$ java FractionCalculator
Simple text-based calculator to compute with fractions.
author: Oliver S. Smart
Enter command: 1/2 - 3/4 * abs
Result is 1/4
Enter command: 8 7/8 - neg +

ERROR you have input two operators: - and +.
	Resetting calculator to its initial state (no operator and 0 as value)
Enter command: 1 + 2
Result is 3
Enter command: + 3
Result is 6
Enter command: 1 / 0

ERROR you cannot divide by zero.
	Resetting calculator to its initial state (no operator and 0 as value)
Enter command: *7

ERROR unrecognized input '*7' cannot process this
	Resetting calculator to its initial state (no operator and 0 as value)
Enter command: * 7
Result is 0
Enter command: Qu
Goodbye