add tests for concat function

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1891865 13f79535-47bb-0310-9956-ffa450edef68

poi/src/test/java/org/apache/poi/ss/formula/functions/TestConcat.java

@@ -0,0 +1,88 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.ss.formula.functions;
+
+import org.apache.poi.hssf.usermodel.*;
+import org.apache.poi.ss.usermodel.CellType;
+import org.apache.poi.ss.usermodel.CellValue;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Test case for CONCAT() - based on https://support.microsoft.com/en-us/office/concat-function-9b1a9a3f-94ff-41af-9736-694cbd6b4ca2?ui=en-us&rs=en-us&ad=us
+ */
+final class TestConcat {
+
+    @Test
+    void testConcatWithStrings() throws IOException {
+        try (HSSFWorkbook wb = initWorkbook1()) {
+            HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);
+            HSSFCell cell = wb.getSheetAt(0).getRow(0).createCell(0);
+            confirmResult(fe, cell, "CONCAT(\"The\",\" \",\"sun\",\" \",\"will\",\" \",\"come\",\" \",\"up\",\" \",\"tomorrow.\")",
+                    "The sun will come up tomorrow.");
+        }
+    }
+
+    @Test
+    void testConcatWithColumns() throws IOException {
+        try (HSSFWorkbook wb = initWorkbook1()) {
+            HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);
+            HSSFCell cell = wb.getSheetAt(0).getRow(0).createCell(0);
+            confirmResult(fe, cell, "CONCAT(B:B, C:C)", "A’sa1a2a4a5a6a7B’sb1b2b4b5b6b7");
+        }
+    }
+
+    @Test
+    void testConcatWithCellRefs() throws IOException {
+        try (HSSFWorkbook wb = initWorkbook1()) {
+            HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);
+            HSSFCell cell = wb.getSheetAt(0).getRow(0).createCell(0);
+            confirmResult(fe, cell, "CONCAT(B2:C8)", "a1b1a2b2a4b4a5b5a6b6a7b7");
+        }
+    }
+
+    private HSSFWorkbook initWorkbook1() {
+        HSSFWorkbook wb = new HSSFWorkbook();
+        HSSFSheet sheet = wb.createSheet();
+        addRow(sheet, 0, null, "A’s", "B’s");
+        for (int i = 1; i <= 7; i++) {
+            if (i != 3) {
+                addRow(sheet, i, null, "a" + i, "b" + i);
+            }
+        }
+        return wb;
+    }
+
+    private void addRow(HSSFSheet sheet, int rownum, String... values) {
+        HSSFRow row = sheet.createRow(rownum);
+        for (int i = 0; i < values.length; i++) {
+            row.createCell(i).setCellValue(values[i]);
+        }
+    }
+
+    private static void confirmResult(HSSFFormulaEvaluator fe, HSSFCell cell, String formulaText, String expectedResult) {
+        cell.setCellFormula(formulaText);
+        fe.notifyUpdateCell(cell);
+        CellValue result = fe.evaluate(cell);
+        assertEquals(result.getCellType(), CellType.STRING);
+        assertEquals(expectedResult, result.getStringValue());
+    }
+}