FitNesse Error : Could not invoke constructor (FitNesse slim) - testing

Question

I am getting an error "Could not invoke constructor" after I tried to test the code through FitNesse.
What can I do to solve this problem?
I have followed instructions from "https://www.softwaretestinghelp.com/getting-started-with-fitnesse-a-collaboration-tool-for-testers-and-developers/" website.
This is the code I wrote to test:
public class Calculator {
public int first, second;
public void setFirst(int first) {
this.first = first;
}
public void setSecond(int second) {
this.second = second;
}
public int addition() {
return (first+second);
}
}
This is what I wrote in FitNesse :
!define TEST_SYSTEM {slim}
!path F:\Eclipse\Workspace\TestFitNesse\bin
| Calculator |
|first |second|addition?|
|4 |2 |6 |
Below is the result I get when I click on the 'Test' button:
Link to view the screenshot of the error

Answer 1

I was just trying to work thru that exact example and getting the same error. It was really frustrating.
The site is incorrect in how it tells you to add the !path value.
It tells you to set it to :
c:\Users\<username>\workspace\test\bin
That is incorrect because:
Running the tests successfully will create the \bin directory so you don't need to create that directory.
The actual path should be:
c:\users\<username>\workspace\test\
We have to include the \test\ portion because the site directs us to create our class in a package named test (at the top of the TestMath java file).
However, if you didn't include that in your .java file then you won't need that portion of the path.
The site also does not tell you explicitly that you need to compile the .java into a .class file either. So, you do need to compile the TestMath.java (using javac) and the drop the TestMath.class file into the directory above.
After you do that, it should work.
I just saw your path is set to:
!path F:\Eclipse\Workspace\TestFitNesse\bin\
If that is what your path is set to, then you need it changed to :
!path F:\Eclipse\Workspace\TestFitNesse\
Of course, if you have included your class in a package by including something like:
package test;
Your path will need to look like:
!path F:\Eclipse\Workspace\TestFitNesse\test\
Then you will drop your compiled .class file in there and it will work.