diff --git a/src/enums/DatatypeEnum.php b/src/enums/DatatypeEnum.php
index 45c7f5d..83ad1bc 100644
--- a/src/enums/DatatypeEnum.php
+++ b/src/enums/DatatypeEnum.php
@@ -66,9 +66,9 @@ class DatatypeEnum
                     return $type;
                 }
             }
-
-            return self::__DEFAULT;
         }
+
+        return self::__DEFAULT;
     }
 
     /**
diff --git a/src/extensions/DatatypeTrait.php b/src/extensions/DatatypeTrait.php
index 6ffd9e2..37012f1 100644
--- a/src/extensions/DatatypeTrait.php
+++ b/src/extensions/DatatypeTrait.php
@@ -23,7 +23,11 @@ trait DatatypeTrait {
      * @return string|false
      */
     private function getMostFrequentDataypeForColumn($datatypes) {
-        array_filter($datatypes);     
+        array_filter($datatypes);
+
+        if (empty($datatypes)){
+            return false;
+        }
 
         // workaround because array_count_values($datatypes) does not work anymore :-(
         foreach ($datatypes as $type) {
diff --git a/tests/methods/DatatypeTest.php b/tests/methods/DatatypeTest.php
new file mode 100644
index 0000000..35c7f9e
--- /dev/null
+++ b/tests/methods/DatatypeTest.php
@@ -0,0 +1,69 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: sgorzaly
+ * Date: 19.02.18
+ * Time: 20:52
+ */
+
+namespace ParseCsv\tests\methods;
+
+use PHPUnit\Framework\TestCase;
+use ParseCsv\enums\DatatypeEnum;
+
+class DatatypeTest extends TestCase
+{
+    public function testSampleIsValidInteger(){
+        $this->assertEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('1'));
+        $this->assertEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('+1'));
+        $this->assertEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('-1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('--1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('test'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('1.0'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('1,0'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('1,1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('0.1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('true'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_INT, DatatypeEnum::getValidTypeFromSample('2018-02-19'));
+    }
+
+    public function testSampleIsValidBool(){
+        $this->assertEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('true'));
+        $this->assertEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('TRUE'));
+        $this->assertEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('false'));
+        $this->assertEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('FALSE'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('FALS'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('test'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('0'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_BOOL, DatatypeEnum::getValidTypeFromSample('0.1'));
+    }
+
+    public function testSampleIsValidFloat(){
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1.0'));
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('-1.1'));
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('+1,1'));
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1,1'));
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1,1'));
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1e-03'));
+        $this->assertEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1e+03'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('test'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1,,1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('1..1'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_FLOAT, DatatypeEnum::getValidTypeFromSample('2018-02-19'));
+    }
+
+    public function testSampleIsValidDate(){
+        $this->assertEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('2018-02-19'));
+        $this->assertEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('18-2-19'));
+        $this->assertEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('01.02.2018'));
+        $this->assertEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('1.2.18'));
+        $this->assertEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('07/31/2018'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('31/07/2018'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('1-2'));
+        $this->assertEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('1.2.'));
+        $this->assertNotEquals(DatatypeEnum::TYPE_DATE, DatatypeEnum::getValidTypeFromSample('test'));
+    }
+
+}
diff --git a/tests/methods/ParseTest.php b/tests/methods/ParseTest.php
index 2ea3f2e..07eb3b7 100644
--- a/tests/methods/ParseTest.php
+++ b/tests/methods/ParseTest.php
@@ -2,7 +2,7 @@
 namespace ParseCsv\tests\methods;
 
 use ParseCsv\Csv;
-use PHPUnit_Framework_TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 
 class ParseTest extends TestCase
 {
diff --git a/tests/methods/SaveTest.php b/tests/methods/SaveTest.php
index 0918b69..6e43b97 100644
--- a/tests/methods/SaveTest.php
+++ b/tests/methods/SaveTest.php
@@ -2,7 +2,7 @@
 namespace ParseCsv\tests\methods;
 
 use ParseCsv\Csv;
-use PHPUnit_Framework_TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 
 class SaveTest extends TestCase
 {
diff --git a/tests/methods/fixtures/datatype.csv b/tests/methods/fixtures/datatype.csv
index 83e6019..d5d848a 100644
--- a/tests/methods/fixtures/datatype.csv
+++ b/tests/methods/fixtures/datatype.csv
@@ -1,5 +1,5 @@
 sep=;
 title;isbn;publishedAt;published;count;price
 Красивая кулинария;5454-5587-3210;21.05.2011;true;1;10.99
-The Wine Connoisseurs;2547-8548-2541;12.12.2011;TRUE;;20,33
+The Wine Connoisseurs;2547-8548-2541;12.12.2011;TRUE;;20.33
 Weißwein;1313-4545-8875;23.02.2012;false;10;10