Merge branch '2.5'

Author: cowtowncoder

src/test/java/com/fasterxml/jackson/dataformat/csv/ser/MultipleWritesTest.java

@@ -0,0 +1,54 @@
+package com.fasterxml.jackson.dataformat.csv.ser;
+
+import java.io.*;
+import java.util.*;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.dataformat.csv.CsvMapper;
+import com.fasterxml.jackson.dataformat.csv.CsvSchema;
+import com.fasterxml.jackson.dataformat.csv.ModuleTestBase;
+
+public class MultipleWritesTest extends ModuleTestBase
+{
+    private final CsvMapper MAPPER = mapperForCsv();
+
+    /**
+     * To reproduce [dataformat-csv#71]: Although ideally one uses
+     * `ObjectWriter.writeValues()` for sequences, we should not
+     * write headers more than once regardless, as long as target
+     * is CsvGenerator which tracks state.
+     */
+    public void testMultipleListWrites() throws Exception
+    {
+        StringWriter sw = new StringWriter();
+
+        CsvSchema.Builder builder = CsvSchema.builder();
+        builder.addColumn("col1");
+        builder.addColumn("col2");
+
+        CsvSchema csvSchema = builder.build().withHeader();
+
+        JsonGenerator gen = MAPPER.getFactory().createGenerator(sw);
+
+        ObjectWriter csvWriter = MAPPER.writer(csvSchema);
+
+        List<String> line1 = new ArrayList<String>();
+        line1.add("line1-val1");
+        line1.add("line1-val2");
+
+        csvWriter.writeValue(gen, line1);
+
+        List<String> line2 = new ArrayList<String>();
+        line2.add("line2-val1");
+        line2.add("line2-val2");
+
+        csvWriter.writeValue(gen, line2);
+
+        String csv = sw.toString().trim();
+        // may get different linefeed on different OSes?
+        csv = csv.replaceAll("[\\r\\n]", "/");
+
+        assertEquals("col1,col2/line1-val1,line1-val2/line2-val1,line2-val2", csv);
+    }
+}