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My idea is to make some testing system for functions, as per the model of CodeForces or TopCoder, but in VBA. There, the users write functions for a problem and the problems are tested vs. predefined tests.

In my case, it will be exactly the same, but the tests would be written on Notepad files.

Long story short, you have to write the function and then the function would be feeded with input parameters from one textfile and the result would be compared with the result from another test file.

The idea of the functions, is that they would be written by a "competitor", as in the aforementioned sites. The functions would be the answer of a predefined problem.

So, let's say that we have defined a problem, which is solvable through this:

If c Mod 2 = 0 Then
    MainTest = a + b + c
Else
    MainTest = a + b - c
End If

Thus, we need to write 2 notepad files in advance, which consist of the input parameters for a, b and c and the results. These are the notepad files:

2 2 2
2 2
2 2 3
4 54 1
2 2
54 23 6
45 45 10

File with results:

6
1
1
58
100
121
100

To make it more presentable, the file with the results, has some runtime errors and wrong calculation errors. Thus this is the result in the immediate window:

Test 1............................................ ok!
Runtime error on 2!
Test 3............................................ ok!
Error on test 4! Expected ->    57   Received ->    58
Runtime error on 5!
Error on test 6! Expected ->    83   Received ->    121
Test 7............................................ ok!

Another possible predefined problem may sound like - "Give me the next character of a string.". Thus "a b c d" would result to "b c d e" and "a z" would be "b a".

And this is the whole competitive testing system:

Option Explicit

Public Sub Main()

    Dim totalTests As Long
    Dim pathInputTests As String
    Dim pathOutputTests As String

    Dim inputTests As Variant
    Dim outputTests As Variant

    Dim cntTests As Long
    Dim cnt As Long

    pathInputTests = "C:\Desktop\Test001.txt"
    pathOutputTests = "C:\Desktop\Result001.txt"

    inputTests = Split(ReadFileLineByLineToString(pathInputTests), vbCrLf)
    outputTests = Split(ReadFileLineByLineToString(pathOutputTests), vbCrLf)

    For cnt = LBound(inputTests) To UBound(inputTests)

        Dim expectedValue   As Variant
        Dim receivedValue   As Variant

        On Error Resume Next

        expectedValue = MainTest(inputTests(cnt))
        receivedValue = outputTests(cnt)

        If Err.Number <> 0 Then
            Debug.Print runtimeError(cnt)
            Err.Clear
        Else
            If expectedValue = receivedValue Then
                Debug.Print positiveResult(cnt)
            Else
                Debug.Print negativeResult(cnt, expectedValue, receivedValue)
            End If
        End If

    Next cnt

End Sub

Public Function runtimeError(ByVal cnt As Long) As String
    cnt = cnt + 1
    runtimeError = "Runtime error on " & cnt & "!"
End Function

Public Function positiveResult(ByVal cnt As Long) As String
    cnt = cnt + 1
    positiveResult = "Test " & cnt & "..................................... ok!"
End Function

Public Function negativeResult(ByVal cnt As Long, expected As Variant, _
                                                received As Variant) As String
    cnt = cnt + 1
    negativeResult = "Error on test " & cnt & "!" & _
                    " Expected -> " & vbTab & expected & vbTab & _
                    " Received -> " & vbTab & received

End Function

'---------------------------------------------------------------------------------------
' Method : MainTest
' Purpose: This is where the competitors paste their solution.
'---------------------------------------------------------------------------------------

Public Function MainTest(ByVal consoleInput As String) As String

    Dim a   As Double
    Dim b   As Double
    Dim c   As Double

    a = Split(consoleInput)(0)
    b = Split(consoleInput)(1)
    c = Split(consoleInput)(2)

    If c Mod 2 = 0 Then
        MainTest = a + b + c
    Else
        MainTest = a + b - c
    End If

End Function

Public Function ReadFileLineByLineToString(path As String) As String

    Dim fileNo As Long
    fileNo = FreeFile

    Open path For Input As #fileNo

    Do While Not EOF(fileNo)
        Dim textRowInput As String
        Line Input #fileNo, textRowInput
        ReadFileLineByLineToString = ReadFileLineByLineToString & textRowInput
        If Not EOF(fileNo) Then
            ReadFileLineByLineToString = ReadFileLineByLineToString & vbCrLf
        End If
    Loop

    Close #fileNo

End Function

The code with the 4 test files is in GitHub here - https://github.com/Vitosh/VBA_personal/tree/master/AlgorithmsWithVBA - feel free to make push requests if you feel like it! :)

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  • \$\begingroup\$ Please see What to do when someone answers. I have rolled back Rev 4 → 3. \$\endgroup\$ Feb 5 '18 at 21:42
  • \$\begingroup\$ @200_success - why did you rolled back? The edit was improving the understanding of the question or I have missed something? \$\endgroup\$
    – Vityata
    Feb 5 '18 at 21:44
  • \$\begingroup\$ We don't allow the code to be modified once an answer has been posted. \$\endgroup\$ Feb 5 '18 at 22:10
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You have split your input code across multiple functions - whereas you should encapsulate your input function to provide a single valid output. The easiest way to explain this is to look at the MainTest Function

  • The input is a single string
  • The MainTest function then has to parse that string
  • There is no error checking to see if the string or the parsing is valid

Inputs and Outputs of MainTest should be consistent with what it does. Your examples are Integer/Long but your code uses Double. Happy this is just brevity for code example sake.

  • Your input is string but it does number operations
  • Your output is string, but the answers inside are numbers
  • All conversions are implicit (see note earlier about no error checking)

A neat MainTest would be like (sticking with Double instead of Long)

Public Function MainTest(ByVal a As Double, b as Double, c as Double) As Double

Similarly, you can modify ReadFileLineByLineToString to return the array. You can then just add to the array as you read each line!

Public Function ReadFileLineByLineToString(path As String) As String()

Of course (arrays)

Dim inputTests() As Variant
Dim outputTests() As Variant

Just before you call expectedValue = MainTest(inputTests(cnt)), Split InputTests(cnt) (e.g. Inputs = split(InputTests(cnt), " ") where Inputs is String() and InputNums = validated Double() from Inputs) and check that you have the right number of elements and that they are numbers (basic error checking). You would then call MainTest as

expectedValue = MainTest(InputNums(0), InputNums(1), InputNums(2))

There are many other places in your code where this sort of thinking can be applied. Consider using Option Strict and well as Option Explicit.

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  • \$\begingroup\$ Hi, thanks for the feedback. Probably you did not get the idea of the code. Its idea is to be a bit more robust, thus if another task is given it should be applicable. Imagine a task, which sounds as trivial as "Just give me the next letter in the alphabet". Then, when the input is "AB", you should return "BC". This is why I am using Strings here Function MainTest(ByVal consoleInput As String) As String. Furthermore, this is VBA, thus Option Strict does not exist there. \$\endgroup\$
    – Vityata
    Feb 3 '18 at 11:37
  • \$\begingroup\$ @Vityata: But you are not doing string manipulation as a MainTest, you are doing arithmetic in this example. Either way, you have to re-write your code base significantly for different operations. My point about using ReadFileLineByLineToString properly still stands. My other points about proper error checking to catch expected errors still stands - you do not have any basic error checking to ensure that your input is correct. For these reasons, your code is not as robust as you think. \$\endgroup\$
    – AJD
    Feb 4 '18 at 4:35
  • \$\begingroup\$ @ThomasInzina: OK, point about Option Strict noted. However, including robust error checking to check inputs is not about "unit tests" - you are not testing anything if the test function itself fails (as opposed to the operation that is being tested). \$\endgroup\$
    – AJD
    Feb 4 '18 at 4:37
  • \$\begingroup\$ @Vityata: Noting that in the OP you mentioned pre-defined tests, of which MainTest is an example. You haven't clarified who writes the function, or where it is implemented. \$\endgroup\$
    – AJD
    Feb 4 '18 at 4:40
  • \$\begingroup\$ That makes sense. \$\endgroup\$
    – user109261
    Feb 4 '18 at 6:33

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