package test;

import static org.junit.Assert.assertEquals;
import static test.TestData.ZERO_LENGTH_MATRIX;
import static test.TestData.MATRIX;
import static test.TestData.SOLUTION;

import org.junit.Before;
import org.junit.Test;

import maxtrix.MatrixNthSmallest;

public class MatrixNthSmallestTest {
	MatrixNthSmallest nthSmallestValueGenerator;
	
	@Before
	public void setUp() {
		nthSmallestValueGenerator = new MatrixNthSmallest();
	}
	
	@Test(expected = IllegalArgumentException.class)
	public void nullMatrixNotAllowed() {
		nthSmallestValueGenerator.getNthSmallestValue(null, 1);
	}
	
	@Test(expected = IllegalArgumentException.class)
	public void zeroLengthOfMatrixNotAllowed() {
		nthSmallestValueGenerator.getNthSmallestValue(ZERO_LENGTH_MATRIX, 1);
	}
	
	@Test(expected = IllegalArgumentException.class)
	public void invalidNValueNotAllowed() {
		nthSmallestValueGenerator.getNthSmallestValue(MATRIX, 0);
	}
	
	@Test
	public void expectedResultVerified() {
		for(int i = 1; i <= MATRIX.length * MATRIX[0].length; i++) {
			assertEquals(nthSmallestValueGenerator.getNthSmallestValue(MATRIX, i), SOLUTION[i-1]);
		}
	}

}