Fix TempFile usage while temp dir was deleted in same process

main/Util/TempFile.cs

@@ -18,11 +18,15 @@ public class TempFile
          */
         public static FileInfo CreateTempFile(String prefix, String suffix)
         {
-
-            if (dir == null)
+            if (string.IsNullOrWhiteSpace(dir))
             {
-                dir = Directory.CreateDirectory(Path.Combine(Path.GetTempPath(), "poifiles")).FullName;
+                string tempDir = Path.Combine(Path.GetTempPath(), "poifiles");
+                dir = Directory.CreateDirectory(tempDir).FullName;
             }
+
+            if (!Directory.Exists(dir))
+                Directory.CreateDirectory(dir);
+
             // Generate a unique new filename 
             string file = Path.Combine(dir, prefix + Guid.NewGuid().ToString() + suffix);
             while (File.Exists(file))
@@ -38,10 +42,15 @@ public static FileInfo CreateTempFile(String prefix, String suffix)
 
         public static string GetTempFilePath(String prefix, String suffix)
         {
-            if (dir == null)
+            if (string.IsNullOrWhiteSpace(dir))
             {
-                dir = Directory.CreateDirectory(Path.Combine(Path.GetTempPath(), "poifiles")).FullName;
+                string tempDir = Path.Combine(Path.GetTempPath(), "poifiles");
+                dir = Directory.CreateDirectory(tempDir).FullName;
             }
+
+            if (!Directory.Exists(dir))
+                Directory.CreateDirectory(dir);
+
             Random rnd = new Random(DateTime.Now.Millisecond);
             Thread.Sleep(10);
             //return prefix + rnd.Next() + suffix;

testcases/main/Util/TestTempFile.cs

@@ -0,0 +1,53 @@
+using NPOI.Util;
+using NUnit.Framework;
+using System.IO;
+
+namespace TestCases.Util
+{
+    /// <summary>
+    /// Tests of creating temp files
+    /// </summary>
+    [TestFixture]
+    [NonParallelizable]
+    internal class TestTempFile
+    {
+        [Test]
+        public void TestCreateTempFile()
+        {
+            FileInfo fileInfo = null;
+            Assert.DoesNotThrow(() => fileInfo = TempFile.CreateTempFile("test", ".xls"));
+
+            Assert.IsTrue(File.Exists(fileInfo.FullName));
+
+            string tempDirPath = Path.GetDirectoryName(fileInfo.FullName);
+
+            if (Directory.Exists(tempDirPath))
+                Directory.Delete(tempDirPath, true);
+
+            Assert.IsFalse(File.Exists(fileInfo.FullName));
+            Assert.IsFalse(Directory.Exists(tempDirPath));
+
+            Assert.DoesNotThrow(() => TempFile.CreateTempFile("test2", ".xls"));
+            Assert.IsTrue(Directory.Exists(tempDirPath));
+        }
+
+        [Test]
+        public void TestGetTempFilePath()
+        {
+            string path = "";
+            Assert.DoesNotThrow(() => path = TempFile.GetTempFilePath("test", ".xls"));
+
+            Assert.IsTrue(!string.IsNullOrWhiteSpace(path));
+
+            string tempDirPath = Path.GetDirectoryName(path);
+
+            if (Directory.Exists(tempDirPath))
+                Directory.Delete(tempDirPath, true);
+
+            Assert.IsFalse(Directory.Exists(tempDirPath));
+
+            Assert.DoesNotThrow(() => TempFile.GetTempFilePath("test", ".xls"));
+            Assert.IsTrue(Directory.Exists(tempDirPath));
+        }
+    }
+}

testcases/ooxml/XSSF/Streaming/GZIPSheetDataWriterTests.cs

@@ -22,6 +22,7 @@ limitations under the License.
 namespace TestCases.XSSF.Streaming
 {
     [TestFixture]
+    [NonParallelizable]
     public class GZIPSheetDataWriterTests
     {
         private GZIPSheetDataWriter _objectToTest;

testcases/ooxml/XSSF/Streaming/SheetDataWriterTests.cs

@@ -24,6 +24,7 @@ limitations under the License.
 namespace TestCases.XSSF.Streaming
 {
     [TestFixture]
+    [NonParallelizable]
     public class SheetDataWriterTests
     {
         private SheetDataWriter _objectToTest;

testcases/ooxml/XSSF/Streaming/TestSXSSFWorkbook.cs

@@ -36,6 +36,7 @@ namespace TestCases.XSSF.Streaming
     using TestCases.Util;
 
     [TestFixture]
+    [NonParallelizable]
     public class TestSXSSFWorkbook : BaseTestXWorkbook
     {