diff --git a/tests/Nazara/Core/ByteArray.cpp b/tests/Nazara/Core/ByteArray.cpp
new file mode 100644
index 000000000..b2b97fe08
--- /dev/null
+++ b/tests/Nazara/Core/ByteArray.cpp
@@ -0,0 +1,216 @@
+#include <Nazara/Core/ByteArray.hpp>
+#include <catch.hpp>
+
+#include <string>
+
+SCENARIO("ByteArray", "[CORE][BYTEARRAY]")
+{
+	GIVEN("Allocate and raw constructor")
+	{
+		NzByteArray byteArray(3);
+
+		THEN("Capacity is 3 and size is 0")
+		{
+			REQUIRE(byteArray.GetSize() == 0);
+			REQUIRE(byteArray.GetCapacity() >= 3);
+		}
+
+		WHEN("We add 'data'")
+		{
+			byteArray.Append("data", 4);
+
+			THEN("We get 'data'")
+			{
+				REQUIRE(byteArray.GetSize() == 4);
+				REQUIRE(byteArray.GetCapacity() >= 4);
+				REQUIRE(byteArray == NzByteArray("data", 4));
+				REQUIRE(byteArray.ToString() == "data");
+			}
+		}
+	}
+
+	GIVEN("Iterator and default constructor")
+	{
+		std::string anotherDataString("anotherData");
+		NzByteArray defaultByte;
+		NzByteArray anotherData(anotherDataString.begin(), anotherDataString.end());
+
+		WHEN("We assign 'anotherData' with iterator")
+		{
+			defaultByte.Assign(anotherData.begin(), anotherData.end());
+			REQUIRE(anotherData == defaultByte);
+			REQUIRE(defaultByte.GetSize() == 11);
+			REQUIRE(defaultByte.GetCapacity() >= 11);
+			REQUIRE(anotherData.GetSize() == 11);
+			REQUIRE(anotherData.GetCapacity() >= 11);
+		}
+	}
+
+	GIVEN("Copy and Move constructor")
+	{
+		NzByteArray originalArray(3, 64);
+
+		WHEN("We copy")
+		{
+			NzByteArray copyByteArray(originalArray);
+
+			THEN("We get a copy")
+			{
+				REQUIRE(copyByteArray == originalArray);
+
+				AND_WHEN("We modify one")
+				{
+					for (NzByteArray::size_type i = 0; i < copyByteArray.GetSize(); ++i)
+						copyByteArray[i] = 46;
+
+					THEN("They are no more equal")
+					{
+						REQUIRE(copyByteArray != originalArray);
+						REQUIRE(copyByteArray == NzByteArray(3, 46));
+						REQUIRE(copyByteArray.GetConstBuffer() != originalArray.GetConstBuffer());
+					}
+				}
+			}
+		}
+
+		WHEN("We move")
+		{
+			NzByteArray moveByteArray(std::move(originalArray));
+
+			THEN("These results are expected")
+			{
+				REQUIRE(moveByteArray == NzByteArray(3, 64));
+				CHECK(originalArray.IsEmpty());
+				REQUIRE(originalArray.GetCapacity() == 0);
+				REQUIRE(moveByteArray.GetConstBuffer() != originalArray.GetConstBuffer());
+
+				AND_WHEN("We modify the empty one")
+				{
+					originalArray.Prepend(NzByteArray(3, 64));
+
+					THEN("They are no more equal")
+					{
+						REQUIRE(moveByteArray == originalArray);
+						REQUIRE(moveByteArray.GetConstBuffer() != originalArray.GetConstBuffer());
+					}
+				}
+			}
+		}
+	}
+
+	GIVEN("Two byte array (abc) and (cba)")
+	{
+		NzByteArray abc("abc", 3);
+		NzByteArray cba;
+		cba = std::move(NzByteArray("cba", 3));
+
+		WHEN("We do some antagonists operations")
+		{
+			THEN("These results are expected")
+			{
+				REQUIRE(abc.Back() == cba.Front());
+
+				abc.Erase(abc.begin(), abc.begin() + 1);
+				abc.Erase(abc.begin());
+
+				cba.Erase(cba.end() - 1, cba.end());
+				cba.Erase(cba.end() - 1);
+
+				REQUIRE(abc == NzByteArray("c", 1));
+				REQUIRE(cba == NzByteArray("c", 1));
+
+				std::string ab("ab");
+				abc.Insert(abc.begin(), ab.begin(), ab.end());
+				cba += NzByteArray("ba", 2);
+
+				REQUIRE(abc == NzByteArray("abc", 3));
+				REQUIRE(cba == NzByteArray("cba", 3));
+
+				abc.PopBack();
+				cba.PopFront();
+
+				REQUIRE(abc == NzByteArray("ab", 2));
+				REQUIRE(cba == NzByteArray("ba", 2));
+
+				abc.PushBack('c');
+				cba.PushFront('c');
+
+				REQUIRE(abc == NzByteArray("abc", 3));
+				REQUIRE(cba == NzByteArray("cba", 3));
+			}
+		}
+	}
+
+	GIVEN("One byte array of capacity 10")
+	{
+		NzByteArray capacityArray(10);
+
+		WHEN("We reserve for 100")
+		{
+			capacityArray.Reserve(100);
+
+			THEN("Capacity is 100")
+			{
+				REQUIRE(capacityArray.GetCapacity() == 100);
+			}
+
+			AND_WHEN("We add information and then shrink to fit")
+			{
+				capacityArray.Prepend("information", 11);
+				capacityArray.ShrinkToFit();
+
+				THEN("Capacity is 11")
+				{
+					REQUIRE(capacityArray.GetCapacity() == 11);
+					REQUIRE(capacityArray.GetSize() == 11);
+				}
+			}
+		}
+
+		NzByteArray::const_pointer oldBuffer = capacityArray.GetConstBuffer();
+		WHEN("We reserve for 5, add 'data' for 4 and then shrink to fit")
+		{
+			capacityArray.Reserve(5);
+			THEN("Capacity is still 10")
+			{
+				REQUIRE(capacityArray.GetCapacity() == 10);
+				REQUIRE(capacityArray.GetSize() == 0);
+				REQUIRE(capacityArray.GetConstBuffer() == oldBuffer);
+			}
+
+			capacityArray.Append("data", 4);
+			capacityArray.ShrinkToFit();
+
+			THEN("Capacity is 4")
+			{
+				REQUIRE(capacityArray.GetConstBuffer() != oldBuffer);
+				REQUIRE(capacityArray.GetCapacity() == 4);
+				REQUIRE(capacityArray.GetSize() == 4);
+			}
+		}
+	}
+
+	GIVEN("Three byte array")
+	{
+		NzByteArray first("hello", 5);
+		NzByteArray second("world", 5);
+		NzByteArray third;
+
+		WHEN("We swap first and third, then second and third and finally third and first")
+		{
+			NzByteArray oldFirst(first);
+			NzByteArray oldSecond(second);
+
+			first.Swap(third);
+			std::swap(second, third);
+			third.Swap(first);
+
+			THEN("First and second have been swapped and third is still empty.")
+			{
+				REQUIRE(oldFirst == second);
+				REQUIRE(oldSecond == first);
+				REQUIRE(third.IsEmpty());
+			}
+		}
+	}
+}
diff --git a/tests/Nazara/Core/Clock.cpp b/tests/Nazara/Core/Clock.cpp
new file mode 100644
index 000000000..9f33a002d
--- /dev/null
+++ b/tests/Nazara/Core/Clock.cpp
@@ -0,0 +1,31 @@
+#include <Nazara/Core/Clock.hpp>
+#include <catch.hpp>
+
+#include <thread>
+
+SCENARIO("Clock", "[CORE][CLOCK]")
+{
+	GIVEN("A clock paused")
+	{
+		nzUInt64 initialTime = 1;
+		NzClock clock(initialTime, true);
+
+		WHEN("We get time")
+		{
+			THEN("Time must be the initialTime")
+			{
+				REQUIRE(clock.GetMicroseconds() == initialTime);
+			}
+
+			AND_WHEN("We unpause it")
+			{
+				clock.Unpause();
+				THEN("Time must not be the initialTime")
+				{
+					std::this_thread::sleep_for(std::chrono::microseconds(10));
+					REQUIRE(clock.GetMicroseconds() != initialTime);
+				}
+			}
+		}
+	}
+}
diff --git a/tests/Nazara/Core/Color.cpp b/tests/Nazara/Core/Color.cpp
new file mode 100644
index 000000000..a07610839
--- /dev/null
+++ b/tests/Nazara/Core/Color.cpp
@@ -0,0 +1,22 @@
+#include <Nazara/Core/Color.hpp>
+#include <catch.hpp>
+
+SCENARIO("Color", "[CORE][COLOR]")
+{
+	GIVEN("Two colors, one red (255) and one gray (128)")
+	{
+		NzColor red(255, 0, 0);
+		NzColor grey(128);
+
+		WHEN("We do operations")
+		{
+			THEN("These results are expected")
+			{
+				red += NzColor(0, 0, 0);
+				grey *= NzColor(255);
+				REQUIRE((red + grey) == NzColor(255, 128, 128));
+				REQUIRE((red * grey) == NzColor(128, 0, 0));
+			}
+		}
+	}
+}
diff --git a/tests/Nazara/Core/Directory.cpp b/tests/Nazara/Core/Directory.cpp
new file mode 100644
index 000000000..203529bb1
--- /dev/null
+++ b/tests/Nazara/Core/Directory.cpp
@@ -0,0 +1,34 @@
+#include <Nazara/Core/Directory.hpp>
+#include <catch.hpp>
+
+SCENARIO("Directory", "[CORE][DIRECTORY]")
+{
+	GIVEN("The current directory")
+	{
+		NzDirectory currentDirectory(NzDirectory::GetCurrent());
+		CHECK(currentDirectory.Exists());
+		currentDirectory.Open();
+
+		WHEN("We create a new directory Test Directory")
+		{
+			NzDirectory::Create("Test Directory");
+
+			THEN("A new directory has been created")
+			{
+				CHECK(NzDirectory::Exists(currentDirectory.GetCurrent() + "/Test Directory"));
+				CHECK(currentDirectory.IsOpen());
+			}
+		}
+
+		AND_WHEN("We delete it")
+		{
+			NzDirectory::Remove(currentDirectory.GetCurrent() + "/Test Directory", true);
+
+			THEN("It doesn't exist anymore")
+			{
+				CHECK(!NzDirectory::Exists(currentDirectory.GetCurrent() + "/Test Directory"));
+			}
+		}
+	}
+}
+
diff --git a/tests/Nazara/Core/Error.cpp b/tests/Nazara/Core/Error.cpp
new file mode 100644
index 000000000..c05e695be
--- /dev/null
+++ b/tests/Nazara/Core/Error.cpp
@@ -0,0 +1,28 @@
+#include <Nazara/Core/Error.hpp>
+#include <catch.hpp>
+
+SCENARIO("Error", "[CORE][ERROR]")
+{
+	nzUInt32 oldFlags = NzError::GetFlags();
+
+	GIVEN("Multiple errors")
+	{
+		WHEN("Calling to error")
+		{
+			THEN("These errors should be written in the log file")
+			{
+				NzError::Error(nzErrorType_Internal, "nzErrorType_Internal");
+				NzError::Error(nzErrorType_Internal, "nzErrorType_Internal", 2, "Error.cpp", "2nd place Internal");
+				REQUIRE("nzErrorType_Internal" == NzError::GetLastError());
+				NzError::Error(nzErrorType_Normal, "nzErrorType_Normal");
+				NzError::Error(nzErrorType_Normal, "nzErrorType_Normal", 2, "Error.cpp", "2nd place Normal");
+				REQUIRE("nzErrorType_Normal" == NzError::GetLastError());
+				NzError::Error(nzErrorType_Warning, "nzErrorType_Warning");
+				NzError::Error(nzErrorType_Warning, "nzErrorType_Warning", 2, "Error.cpp", "2nd place Warning");
+				REQUIRE("nzErrorType_Warning" == NzError::GetLastError());
+			}
+		}
+	}
+
+	NzError::SetFlags(oldFlags);
+}
diff --git a/tests/Nazara/Core/File.cpp b/tests/Nazara/Core/File.cpp
new file mode 100644
index 000000000..1527632f8
--- /dev/null
+++ b/tests/Nazara/Core/File.cpp
@@ -0,0 +1,53 @@
+#include <Nazara/Core/File.hpp>
+#include <catch.hpp>
+
+SCENARIO("File", "[CORE][FILE]")
+{
+	GIVEN("One file")
+	{
+		WHEN("We create a new file")
+		{
+			NzFile file("Test File.txt", nzOpenMode_ReadWrite);
+			REQUIRE(file.GetDirectory() == NzDirectory::GetCurrent() + NAZARA_DIRECTORY_SEPARATOR);
+			CHECK(file.IsOpen());
+
+			THEN("We are allowed to write 3 times 'Test String'")
+			{
+				const char message[12] = "Test String"; // 11 + '\0'
+				NzByteArray byteArray(message, 11);
+				file.Write("Test String");
+				file.Write(byteArray);
+				file.Write(message, sizeof(char), 11);
+			}
+
+			AND_THEN("We can retrieve 3 times 'Test String'")
+			{
+				char message[12];
+				REQUIRE(file.Read(message, 11) == 11);
+				message[11] = '\0';
+				REQUIRE(NzString(message) == "Test String");
+
+				REQUIRE(file.Read(message, sizeof(char), 11) == 11);
+				message[11] = '\0';
+				REQUIRE(NzString(message) == "Test String");
+			}
+
+			AND_THEN("We close it")
+			{
+				file.Close();
+				REQUIRE(file.GetSize() == 33U);
+				CHECK(!file.IsOpen());
+			}
+		}
+
+		WHEN("We delete this file")
+		{
+			NzFile::Delete("Test File.txt");
+
+			THEN("It doesn't exist anymore")
+			{
+				CHECK(!NzFile::Exists("Test File.txt"));
+			}
+		}
+	}
+}
diff --git a/tests/Nazara/Core/String.cpp b/tests/Nazara/Core/String.cpp
new file mode 100644
index 000000000..88daf56da
--- /dev/null
+++ b/tests/Nazara/Core/String.cpp
@@ -0,0 +1,111 @@
+#include <Nazara/Core/String.hpp>
+#include <catch.hpp>
+
+SCENARIO("String", "[CORE][STRING]")
+{
+	GIVEN("One string 'a'")
+	{
+		NzString aDefaultString(1, 'a');
+
+		WHEN("We add information")
+		{
+			aDefaultString.Append("Default");
+			aDefaultString.Insert(aDefaultString.GetSize(), "String");
+
+			THEN("The result should be 'aDefaultString'")
+			{
+				REQUIRE(aDefaultString == "aDefaultString");
+				REQUIRE(aDefaultString.GetSize() == 14);
+				REQUIRE(aDefaultString.GetCapacity() >= 14);
+			}
+
+			AND_WHEN("We test Contains and Find")
+			{
+				THEN("These results are expected")
+				{
+					CHECK(aDefaultString.Contains('D'));
+					CHECK(aDefaultString.Contains("String", 3));
+					CHECK(aDefaultString.Contains(NzString("sTRING"), 3, NzString::CaseInsensitive));
+					REQUIRE(aDefaultString.FindLast('g') == aDefaultString.GetSize() - 1);
+					CHECK(aDefaultString.EndsWith('G', NzString::CaseInsensitive));
+					aDefaultString.Append(" ng bla");
+					REQUIRE(aDefaultString.FindWord("ng") == aDefaultString.GetSize() - 6);
+					//TODO REQUIRE(aDefaultString.FindWord(NzString("ng")) == aDefaultString.GetSize() - 6);
+					CHECK(aDefaultString.StartsWith("aD"));
+				}
+			}
+		}
+
+		WHEN("We do operators")
+		{
+			aDefaultString[0] = 'a';
+			aDefaultString += "Default";
+			aDefaultString = aDefaultString + "String";
+
+			THEN("The result should be 'aDefaultString'")
+			{
+				REQUIRE(aDefaultString == "aDefaultString");
+				REQUIRE(aDefaultString.GetSize() == 14);
+				REQUIRE(aDefaultString.GetCapacity() >= 14);
+			}
+
+			AND_WHEN("We test Count")
+			{
+				THEN("These results are expected")
+				{
+					REQUIRE(aDefaultString.Count('D') == 1);
+					REQUIRE(aDefaultString.Count("t", 2) == 2);
+				}
+			}
+		}
+	}
+
+	GIVEN("The string of number 16 in base 16")
+	{
+		NzString number16;
+
+		CHECK(number16.IsEmpty());
+		CHECK(number16.IsNull());
+
+		WHEN("We assign to number 16")
+		{
+			number16 = NzString::Number(16, 16);
+
+			THEN("These results are expected")
+			{
+				CHECK(number16.IsNumber(16));
+				number16.Prepend("0x");
+				REQUIRE(number16.GetSize() == 4);
+				REQUIRE(number16.GetCapacity() >= 4);
+				REQUIRE(number16.SubStringFrom('x', 1) == "10");
+			}
+		}
+	}
+
+	/* TODO
+	GIVEN("One unicode string")
+	{
+		NzString unicodeString = NzString::Unicode(U"àéçœÂ官話");
+
+		WHEN("We convert to other UTF")
+		{
+			REQUIRE(unicodeString.GetSize() == 7);
+			REQUIRE(unicodeString.GetCapacity() >= 7);
+			CHECK(unicodeString.Contains("官"));
+
+			THEN("The result should be the identity")
+			{
+				char* utf8 = unicodeString.GetUtf8Buffer();
+				NzString utf8String = NzString::Unicode(utf8);
+				char16_t* utf16 = unicodeString.GetUtf16Buffer();
+				NzString utf16String = NzString::Unicode(utf16);
+				char32_t* utf32 = unicodeString.GetUtf32Buffer();
+				NzString utf32String = NzString::Unicode(utf32);
+
+				REQUIRE(utf8String == utf16String);
+				REQUIRE(utf16String == utf32String);
+			}
+		}
+	}*/
+}
+
diff --git a/tests/Nazara/Core/StringStream.cpp b/tests/Nazara/Core/StringStream.cpp
new file mode 100644
index 000000000..62f0b794e
--- /dev/null
+++ b/tests/Nazara/Core/StringStream.cpp
@@ -0,0 +1,71 @@
+#include <Nazara/Core/StringStream.hpp>
+#include <catch.hpp>
+
+SCENARIO("StringStream", "[CORE][STRINGSTREAM]")
+{
+	GIVEN("A string stream")
+	{
+		NzStringStream stringstream("default");
+
+		WHEN("We add bool and char")
+		{
+			stringstream << true;
+
+			char valueCharSigned = 64;
+			stringstream << valueCharSigned;
+			unsigned char valueCharUnsigned = 64;
+			stringstream << valueCharUnsigned;
+
+			REQUIRE(stringstream.ToString() == "defaulttrue@@");
+		}
+
+		AND_WHEN("We add short and int")
+		{
+			short valueShortSigned = -3;
+			stringstream << valueShortSigned;
+			unsigned short valueShortUnsigned = 3;
+			stringstream << valueShortUnsigned;
+
+			int valueIntSigned = -3;
+			stringstream << valueIntSigned;
+			unsigned int valueIntUnsigned = 3;
+			stringstream << valueIntUnsigned;
+
+			REQUIRE(stringstream.ToString() == "default-33-33");
+		}
+
+		AND_WHEN("We add long and long long")
+		{
+			long valueLongSigned = -3;
+			stringstream << valueLongSigned;
+			unsigned long valueLongUnsigned = 3;
+			stringstream << valueLongUnsigned;
+
+			long long valueLongLongSigned = -3;
+			stringstream << valueLongLongSigned;
+			unsigned long long valueLongLongUnsigned = 3;
+			stringstream << valueLongLongUnsigned;
+
+			REQUIRE(stringstream.ToString() == "default-33-33");
+		}
+
+		AND_WHEN("We add floating points")
+		{
+			stringstream << 3.f;
+			stringstream << 3.0;
+			stringstream << 3.0L;
+
+			REQUIRE(stringstream.ToString() == "default333");
+		}
+
+		AND_WHEN("We add string and pointer")
+		{
+			stringstream << "3";
+			stringstream << std::string("3");
+			stringstream << NzString("3");
+			stringstream << static_cast<void*>(nullptr);
+
+			REQUIRE(stringstream.ToString() == (NzString("default3330x") + NzString(sizeof(void*) * 2, "0")));
+		}
+	}
+}