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Validating DataSet Operations in MPAndroidChart

This test suite validates the core functionality of DataSet handling in MPAndroidChart, focusing on data point management and value retrieval operations. It ensures reliable chart data manipulation through comprehensive unit testing of the ScatterDataSet implementation.

Test Coverage Overview

The test suite provides extensive coverage of DataSet operations including:

Min/max value calculations for both X and Y coordinates
Entry addition and removal operations
Ordered entry insertion functionality
X-value based entry retrieval with different rounding modes
Handling of duplicate X-value entries

Implementation Analysis

The testing approach employs JUnit to validate ScatterDataSet behavior through discrete test methods. Each test focuses on specific functionality using assertions to verify expected outcomes. The implementation demonstrates systematic validation of data management operations with precise floating-point comparisons.

Technical Details

Testing Configuration:

JUnit testing framework
Assert methods for equality checking with delta tolerance
ArrayList implementation for entry storage
Custom Entry class for data point representation
DataSet.Rounding enum for value retrieval control

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test methods for specific functionality
Comprehensive edge case coverage
Precise floating-point comparisons using delta values
Clear test method naming conventions
Thorough validation of data structure operations

philjay/mpandroidchart

MPChartLib/src/test/java/com/github/mikephil/charting/test/DataSetTest.java

            
package com.github.mikephil.charting.test;

import com.github.mikephil.charting.data.DataSet;
import com.github.mikephil.charting.data.Entry;
import com.github.mikephil.charting.data.ScatterDataSet;

import org.junit.Test;

import java.util.ArrayList;
import java.util.List;

import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertFalse;
import static junit.framework.Assert.assertTrue;

/**
 * Created by philipp on 31/05/16.
 */
public class DataSetTest {

    @Test
    public void testCalcMinMax() {

        List<Entry> entries = new ArrayList<Entry>();
        entries.add(new Entry(10, 10));
        entries.add(new Entry(15, 2));
        entries.add(new Entry(21, 5));

        ScatterDataSet set = new ScatterDataSet(entries, "");

        assertEquals(10f, set.getXMin(), 0.01f);
        assertEquals(21f, set.getXMax(), 0.01f);

        assertEquals(2f, set.getYMin(), 0.01f);
        assertEquals(10f, set.getYMax(), 0.01f);

        assertEquals(3, set.getEntryCount());

        set.addEntry(new Entry(25, 1));

        assertEquals(10f, set.getXMin(), 0.01f);
        assertEquals(25f, set.getXMax(), 0.01f);

        assertEquals(1f, set.getYMin(), 0.01f);
        assertEquals(10f, set.getYMax(), 0.01f);

        assertEquals(4, set.getEntryCount());

        set.removeEntry(3);

        assertEquals(10f, set.getXMin(), 0.01f);
        assertEquals(21, set.getXMax(), 0.01f);

        assertEquals(2f, set.getYMin(), 0.01f);
        assertEquals(10f, set.getYMax(), 0.01f);
    }

    @Test
    public void testAddRemoveEntry() {

        List<Entry> entries = new ArrayList<Entry>();
        entries.add(new Entry(10, 10));
        entries.add(new Entry(15, 2));
        entries.add(new Entry(21, 5));

        ScatterDataSet set = new ScatterDataSet(entries, "");

        assertEquals(3, set.getEntryCount());

        set.addEntryOrdered(new Entry(5, 1));

        assertEquals(4, set.getEntryCount());

        assertEquals(5, set.getXMin(), 0.01f);
        assertEquals(21, set.getXMax(), 0.01f);

        assertEquals(1f, set.getYMin(), 0.01f);
        assertEquals(10f, set.getYMax(), 0.01f);

        assertEquals(5, set.getEntryForIndex(0).getX(), 0.01f);
        assertEquals(1, set.getEntryForIndex(0).getY(), 0.01f);

        set.addEntryOrdered(new Entry(20, 50));

        assertEquals(5, set.getEntryCount());

        assertEquals(20, set.getEntryForIndex(3).getX(), 0.01f);
        assertEquals(50, set.getEntryForIndex(3).getY(), 0.01f);

        assertTrue(set.removeEntry(3));

        assertEquals(4, set.getEntryCount());

        assertEquals(21, set.getEntryForIndex(3).getX(), 0.01f);
        assertEquals(5, set.getEntryForIndex(3).getY(), 0.01f);

        assertEquals(5, set.getEntryForIndex(0).getX(), 0.01f);
        assertEquals(1, set.getEntryForIndex(0).getY(), 0.01f);

        assertTrue(set.removeFirst());

        assertEquals(3, set.getEntryCount());

        assertEquals(10, set.getEntryForIndex(0).getX(), 0.01f);
        assertEquals(10, set.getEntryForIndex(0).getY(), 0.01f);

        set.addEntryOrdered(new Entry(15, 3));

        assertEquals(4, set.getEntryCount());

        assertEquals(15, set.getEntryForIndex(1).getX(), 0.01f);
        assertEquals(3, set.getEntryForIndex(1).getY(), 0.01f);

        assertEquals(21, set.getEntryForIndex(3).getX(), 0.01f);
        assertEquals(5, set.getEntryForIndex(3).getY(), 0.01f);

        assertTrue(set.removeLast());

        assertEquals(3, set.getEntryCount());

        assertEquals(15, set.getEntryForIndex(2).getX(), 0.01f);
        assertEquals(2, set.getEntryForIndex(2).getY(), 0.01f);

        assertTrue(set.removeLast());

        assertEquals(2, set.getEntryCount());

        assertTrue(set.removeLast());

        assertEquals(1, set.getEntryCount());

        assertEquals(10, set.getEntryForIndex(0).getX(), 0.01f);
        assertEquals(10, set.getEntryForIndex(0).getY(), 0.01f);

        assertTrue(set.removeLast());

        assertEquals(0, set.getEntryCount());

        assertFalse(set.removeLast());
        assertFalse(set.removeFirst());
    }

    @Test
    public void testGetEntryForXValue() {

        List<Entry> entries = new ArrayList<Entry>();
        entries.add(new Entry(10, 10));
        entries.add(new Entry(15, 5));
        entries.add(new Entry(21, 5));

        ScatterDataSet set = new ScatterDataSet(entries, "");

        Entry closest = set.getEntryForXValue(17, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(15, closest.getX(), 0.01f);
        assertEquals(5, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(17, Float.NaN, DataSet.Rounding.DOWN);
        assertEquals(15, closest.getX(), 0.01f);
        assertEquals(5, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(15, Float.NaN, DataSet.Rounding.DOWN);
        assertEquals(15, closest.getX(), 0.01f);
        assertEquals(5, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(14, Float.NaN, DataSet.Rounding.DOWN);
        assertEquals(10, closest.getX(), 0.01f);
        assertEquals(10, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(17, Float.NaN, DataSet.Rounding.UP);
        assertEquals(21, closest.getX(), 0.01f);
        assertEquals(5, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(21, Float.NaN, DataSet.Rounding.UP);
        assertEquals(21, closest.getX(), 0.01f);
        assertEquals(5, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(21, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(21, closest.getX(), 0.01f);
        assertEquals(5, closest.getY(), 0.01f);
    }

    @Test
    public void testGetEntryForXValueWithDuplicates() {

        // sorted list of values (by x position)
        List<Entry> values = new ArrayList<Entry>();
        values.add(new Entry(0, 10));
        values.add(new Entry(1, 20));
        values.add(new Entry(2, 30));
        values.add(new Entry(3, 40));
        values.add(new Entry(3, 50)); // duplicate
        values.add(new Entry(4, 60));
        values.add(new Entry(4, 70)); // duplicate
        values.add(new Entry(5, 80));
        values.add(new Entry(6, 90));
        values.add(new Entry(7, 100));
        values.add(new Entry(8, 110));
        values.add(new Entry(8, 120)); // duplicate

        ScatterDataSet set = new ScatterDataSet(values, "");

        Entry closest = set.getEntryForXValue(0, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(0, closest.getX(), 0.01f);
        assertEquals(10, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(5, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(5, closest.getX(), 0.01f);
        assertEquals(80, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(5.4f, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(5, closest.getX(), 0.01f);
        assertEquals(80, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(4.6f, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(5, closest.getX(), 0.01f);
        assertEquals(80, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(7, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(7, closest.getX(), 0.01f);
        assertEquals(100, closest.getY(), 0.01f);

        closest = set.getEntryForXValue(4f, Float.NaN, DataSet.Rounding.CLOSEST);
        assertEquals(4, closest.getX(), 0.01f);
        assertEquals(60, closest.getY(), 0.01f);

        List<Entry> entries = set.getEntriesForXValue(4f);
        assertEquals(2, entries.size());
        assertEquals(60, entries.get(0).getY(), 0.01f);
        assertEquals(70, entries.get(1).getY(), 0.01f);

        entries = set.getEntriesForXValue(3.5f);
        assertEquals(0, entries.size());

        entries = set.getEntriesForXValue(2f);
        assertEquals(1, entries.size());
        assertEquals(30, entries.get(0).getY(), 0.01f);
    }
}