poi/src/testcases/org/apache/poi/hssf/record/aggregates/TestSharedValueManager.java

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package org.apache.poi.hssf.record.aggregates;

import java.util.Collection;
import java.util.HashMap;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import org.apache.poi.hssf.HSSFTestDataSamples;
import org.apache.poi.hssf.record.Record;
import org.apache.poi.hssf.record.SharedFormulaRecord;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.usermodel.RecordInspector;

/**
 * Tests for {@link SharedValueManager}
 *
 * @author Josh Micich
 */
public final class TestSharedValueManager extends TestCase {

	/**
	 * This Excel workbook contains two sheets that each have a pair of overlapping shared formula
	 * ranges.  The first sheet has one row and one column shared formula ranges which intersect.
	 * The second sheet has two column shared formula ranges - one contained within the other.
	 * These shared formula ranges were created by fill-dragging a single cell formula across the
	 * desired region.  The larger shared formula ranges were placed first.<br/>
	 *
	 * There are probably many ways to produce similar effects, but it should be noted that Excel
	 * is quite temperamental in this regard.  Slight variations in technique can cause the shared
	 * formulas to spill out into plain formula records (which would make these tests pointless).
	 *
	 */
	private static final String SAMPLE_FILE_NAME = "overlapSharedFormula.xls";
	/**
	 * Some of these bugs are intermittent, and the test author couldn't think of a way to write
	 * test code to hit them bug deterministically. The reason for the unpredictability is that
	 * the bugs depended on the {@link SharedFormulaRecord}s being searched in a particular order.
	 * At the time of writing of the test, the order was being determined by the call to {@link
	 * Collection#toArray(Object[])} on {@link HashMap#values()} where the items in the map were
	 * using default {@link Object#hashCode()}<br/>
	 */
	private static final int MAX_ATTEMPTS=5;

	/**
	 * This bug happened when there were two or more shared formula ranges that overlapped.  POI
	 * would sometimes associate formulas in the overlapping region with the wrong shared formula
	 */
	public void testPartiallyOverlappingRanges() {
		Record[] records;

		int attempt=1;
		do {
			HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook(SAMPLE_FILE_NAME);

			HSSFSheet sheet = wb.getSheetAt(0);
			RecordInspector.getRecords(sheet, 0);
			assertEquals("1+1", sheet.getRow(2).getCell(0).getCellFormula());
			if ("1+1".equals(sheet.getRow(3).getCell(0).getCellFormula())) {
				throw new AssertionFailedError("Identified bug - wrong shared formula record chosen"
						+ " (attempt " + attempt + ")");
			}
			assertEquals("2+2", sheet.getRow(3).getCell(0).getCellFormula());
			records = RecordInspector.getRecords(sheet, 0);
		} while (attempt++ < MAX_ATTEMPTS);

		int count=0;
		for (int i = 0; i < records.length; i++) {
			if (records[i] instanceof SharedFormulaRecord) {
				count++;
			}
		}
		assertEquals(2, count);
	}

	/**
	 * This bug occurs for similar reasons to the bug in {@link #testPartiallyOverlappingRanges()}
	 * but the symptoms are much uglier - serialization fails with {@link NullPointerException}.<br/>
	 */
	public void testCompletelyOverlappedRanges() {
		Record[] records;

		int attempt=1;
		do {
			HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook(SAMPLE_FILE_NAME);

			HSSFSheet sheet = wb.getSheetAt(1);
			try {
				records = RecordInspector.getRecords(sheet, 0);
			} catch (NullPointerException e) {
				throw new AssertionFailedError("Identified bug " +
						"- cannot reserialize completely overlapped shared formula"
						+ " (attempt " + attempt + ")");
			}
		} while (attempt++ < MAX_ATTEMPTS);

		int count=0;
		for (int i = 0; i < records.length; i++) {
			if (records[i] instanceof SharedFormulaRecord) {
				count++;
			}
		}
		assertEquals(2, count);
	}

	/**
	 * Tests fix for a bug in the way shared formula cells are associated with shared formula
	 * records.  Prior to this fix, POI would attempt to use the upper left corner of the
	 * shared formula range as the locator cell.  The correct cell to use is the 'first cell'
	 * in the shared formula group which is not always the top left cell.  This is possible
	 * because shared formula groups may be sparse and may overlap.<br/>
	 *
	 * Two existing sample files (15228.xls and ex45046-21984.xls) had similar issues.
	 * These were not explored fully, but seem to be fixed now.
	 */
	public void testRecalculateFormulas47747() {

		/*
		 * ex47747-sharedFormula.xls is a heavily cut-down version of the spreadsheet from
		 * the attachment (id=24176) in Bugzilla 47747.  This was done to make the sample
		 * file smaller, which hopefully allows the special data encoding condition to be
		 * seen more easily.  Care must be taken when modifying this file since the
		 * special conditions are easily destroyed (which would make this test useless).
		 * It seems that removing the worksheet protection has made this more so - if the
		 * current file is re-saved in Excel(2007) the bug condition disappears.
		 *
		 *
		 * Using BiffViewer, one can see that there are two shared formula groups representing
		 * the essentially same formula over ~20 cells.  The shared group ranges overlap and
		 * are A12:Q20 and A20:Q27.  The locator cell ('first cell') for the second group is
		 * Q20 which is not the top left cell of the enclosing range.  It is this specific
		 * condition which caused the bug to occur
		 */
		HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook("ex47747-sharedFormula.xls");

		// pick out a cell from within the second shared formula group
		HSSFCell cell = wb.getSheetAt(0).getRow(23).getCell(0);
		String formulaText;
		try {
			formulaText = cell.getCellFormula();
			// succeeds if the formula record has been associated
			// with the second shared formula group
		} catch (RuntimeException e) {
			// bug occurs if the formula record has been associated
			// with the first shared formula group
			if ("Shared Formula Conversion: Coding Error".equals(e.getMessage())) {
				throw new AssertionFailedError("Identified bug 47747");
			}
			throw e;
		}
		assertEquals("$AF24*A$7", formulaText);
	}
}