doc correction

tests/math/testpimathmatrix.cpp

@@ -34,24 +34,22 @@ bool cmpMatrixWithValue(PIMathMatrix<double> matrix, double val)
 
 TEST(PIMathMatrix_Test, identity)
 {
-    PIMathMatrix<double> origMatr;
-    PIMathMatrix<double> matrix;
-    int i;
-    bool b;
-    matrix = origMatr.identity(3, 3);
-    for(i = 0; i < 3; i++)
-    {
-        if(matrix[i][i] == 1.0)
-        {
-            b = true;
-        }
-        else
-        {
-            b = false;
-            break;
+    auto matrix = PIMathMatrix<double>::identity(3, 3);
+    for(int i = 0; i < 3; i++){
+        if(matrix[i][i] != 1.0){
+            ASSERT_TRUE(false);
         }
     }
-    ASSERT_TRUE(b);
+    for(int i = 0; i < 3; i++){
+        for(int j = 0; j < 3; j++){
+            if(i != j){
+                if(matrix[i][j] != 0.0){
+                    ASSERT_TRUE(false);
+                }
+            }
+        }
+    }
+    ASSERT_TRUE(true);
 }
 
 TEST(PIMathMatrix_Test, matrixRow)