Tests of crack calculator were added

StructureHelperCommon/Models/Calculators/IAccuracy.cs

@@ -1,8 +1,17 @@
 namespace StructureHelperCommon.Models.Calculators
 {
+    /// <summary>
+    /// Rate of calculation which based on iteration of finished accuracy
+    /// </summary>
     public interface IAccuracy
     {
+        /// <summary>
+        /// Max accuracy of iteration
+        /// </summary>
         double IterationAccuracy { get; set; }
+        /// <summary>
+        /// Limit iteration count for calculation
+        /// </summary>
         int MaxIterationCount { get; set; }
     }
 }