Code cleanup

Author: sakno

src/DotNext.Tests/ResultTests.cs

@@ -72,16 +72,15 @@ public static void Operators()
         var result = new Result<int>(10);
         if (result) { }
         else Fail("Unexpected Result state");
-        if (!result) Fail("Unexpected Result state");
+        False(!result);
         Equal(10, (int)result);
         Equal("10", result.ToString());
         Optional<int> opt = result;
         Equal(10, opt);
         Equal(10, result.OrInvoke(static () => 20));
         result = new Result<int>(new Exception());
         if (result) Fail("Unexpected Result state");
-        if (!result) { }
-        else Fail("Unexpected Result state");
+        True(!result);
         Equal(20, result.OrInvoke(static () => 20));
         opt = result;
         False(opt.HasValue);
@@ -93,16 +92,15 @@ public static void Operators2()
         var result = new Result<int, EnvironmentVariableTarget>(10);
         if (result) { }
         else Fail("Unexpected Result state");
-        if (!result) Fail("Unexpected Result state");
+        False(!result);
         Equal(10, (int)result);
         Equal("10", result.ToString());
         Optional<int> opt = result;
         Equal(10, opt);
         Equal(10, result.OrInvoke(static () => 20));
         result = new Result<int, EnvironmentVariableTarget>(EnvironmentVariableTarget.Machine);
         if (result) Fail("Unexpected Result state");
-        if (!result) { }
-        else Fail("Unexpected Result state");
+        True(!result);
         Equal(20, result.OrInvoke(static () => 20));
         opt = result;
         False(opt.HasValue);