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Java Unit Testing in Java What to Test Rules rule!

@Rule

Aren't rules awesome?! I've done all the importing for you here of the rule, but I'd like you to use it in the constructingLargerThanAlphabetNotAllowed test. It currently throws an exception. Can you use thrown rule I created for you to make sure we are getting the expected message from the assertion?

PS. I am running the unit tests when you click preview. You can grab the error message from the output.

I put" (expected = ExpectedException.class)" after @Test. But something is wrong. Could you help me?

com/teamtreehouse/vending/AlphaNumericChooserTest.java
package com.teamtreehouse.vending;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;


import static org.junit.Assert.*;

public class AlphaNumericChooserTest {

    private AlphaNumericChooser chooser;

    // I added this rule setup code for you, thank me later. ;)
    @Rule
    public ExpectedException thrown = ExpectedException.none();

    @Before
    public void setUp() throws Exception {
        chooser = new AlphaNumericChooser(26, 10);
    }

    @Test
    public void validInputReturnsProperLocation() throws Exception {
        AlphaNumericChooser.Location loc = chooser.locationFromInput("B4");

        assertEquals("proper row", 1, loc.getRow());
        assertEquals("proper column", 3, loc.getColumn());
    }

    @Test(expected = InvalidLocationException.class)
    public void choosingWrongInputIsNotAllowed() throws Exception {
        chooser.locationFromInput("WRONG");
    }

    @Test(expected = InvalidLocationException.class)
    public void choosingLargerThanMaxIsNotAllowed() throws Exception {
        chooser.locationFromInput("B52");
    }

    @Test(expected = ExpectedException.class)
    public void constructingLargerThanAlphabetNotAllowed() throws Exception {
          throws.expect(IllegalArgumentException.class);
             throws.expectMessege("Maximum rows supported is 26");
        new AlphaNumericChooser(27, 10);




}
com/teamtreehouse/vending/AlphaNumericChooser.java
package com.teamtreehouse.vending;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class AlphaNumericChooser extends AbstractChooser {
    private int ALPHA_FIRST = (int) 'A';
    private int ALPHA_LAST = (int) 'Z';

    public AlphaNumericChooser(int maxRows, int maxColumns) {
        super(maxRows, maxColumns);
        int maxAllowedAlpha = (ALPHA_LAST - ALPHA_FIRST) + 1;
        if (maxRows > maxAllowedAlpha) {
            throw new IllegalArgumentException("Maximum rows supported is " + maxAllowedAlpha);
        }
    }

    @Override
    public Location locationFromInput(String input) throws InvalidLocationException {
        Pattern pattern = Pattern.compile("^(?<row>[a-zA-Z]{1})(?<column>[0-9]+)$");
        Matcher matcher = pattern.matcher(input);
        if (!matcher.matches()) {
            throw new InvalidLocationException("Invalid buttons");
        }
        int row = inputAsRow(matcher.group("row"));
        int column = inputAsColumn(matcher.group("column"));
        return new Location(row, column);

    }

    private int inputAsRow(String rowInput) {
        rowInput = rowInput.toUpperCase();
        return (int) rowInput.charAt(0) - ALPHA_FIRST;

    }

    private int inputAsColumn(String columnInput) {
        int columnAsInt = Integer.parseInt(columnInput);
        return columnAsInt - 1;
    }
}
com/teamtreehouse/vending/AbstractChooser.java
package com.teamtreehouse.vending;

public abstract class AbstractChooser {
    private final int maxRows;
    private final int maxColumns;

    public class Location {
        private final int row;
        private final int column;

        protected Location(int row, int column) throws InvalidLocationException {
            if (row > maxRows || column > maxColumns) {
                throw new InvalidLocationException("Invalid Location");
            }
            this.row = row;
            this.column = column;
        }

        public int getRow() {
            return row;
        }

        public int getColumn() {
            return column;
        }
    }

    public AbstractChooser(int maxRows, int maxColumns) {
        this.maxRows = maxRows;
        this.maxColumns = maxColumns;
    }

    public abstract Location locationFromInput(String input) throws InvalidLocationException;
}
com/teamtreehouse/vending/InvalidLocationException.java
package com.teamtreehouse.vending;

public class InvalidLocationException extends Exception {
    public InvalidLocationException(String s) {
        super(s);
    }
}

2 Answers

Mihai Craciun
Mihai Craciun
13,520 Points

You don't need the (expected = ExpectedException.class) in the @Test annotation because in the @Rule annotation we already create an ExpectedException variable you used inside the method

 @Test
    public void constructingLargerThanAlphabetNotAllowed() throws Exception {
        thrown.expect(IllegalArgumentException.class);
        thrown.expectMessage("Maximum rows supported is 26");
        new AlphaNumericChooser(27, 10);
    }

Thank you! I made it!!

Mihai Craciun
Mihai Craciun
13,520 Points

You're welcome :) ! I'm glad I could help. Happy coding!