From a154e1443974c1d128d007a7a40a8f2a39482816 Mon Sep 17 00:00:00 2001
From: James Goppert <james.goppert@gmail.com>
Date: Fri, 3 Feb 2017 17:24:15 -0500
Subject: [PATCH] Fix coverage for inverse.

---
 matrix/SquareMatrix.hpp |  5 ++---
 test/inverse.cpp        | 25 ++++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/matrix/SquareMatrix.hpp b/matrix/SquareMatrix.hpp
index fe98cbefb0..912a27a31a 100644
--- a/matrix/SquareMatrix.hpp
+++ b/matrix/SquareMatrix.hpp
@@ -232,9 +232,8 @@ bool inv(const SquareMatrix<Type, M> & A, SquareMatrix<Type, M> & inv)
             // divide by the factor
             // on current
             // term to be solved
-            if(fabsf(U(i,i)) < 1e-8f) {
-                return false;
-            }
+            //
+            // we know that U(i, i) != 0 from above
             P(i, c) /= U(i, i);
         }
     }
diff --git a/test/inverse.cpp b/test/inverse.cpp
index 0f7ef054ad..3c157388c0 100644
--- a/test/inverse.cpp
+++ b/test/inverse.cpp
@@ -82,7 +82,30 @@ int main()
     SquareMatrix<float, 3> A3(data3);
     SquareMatrix<float, 3> A3_I = inv(A3);
     SquareMatrix<float, 3> A3_I_check(data3_check);
-    TEST((A3_I - A3_I_check).abs().max() < 1e-5);
+    TEST(isEqual(inv(A3), A3_I_check));
+    TEST(isEqual(A3_I, A3_I_check));
+    TEST(A3.I(A3_I));
+    TEST(isEqual(A3_I, A3_I_check));
+
+    // cover singular matrices
+    A3(0, 0) = 0;
+    A3(0, 1) = 0;
+    A3(0, 2) = 0;
+    A3_I = inv(A3);
+    SquareMatrix<float, 3>  Z3 = zeros<float, 3, 3>();
+    TEST(!A3.I(A3_I));
+    TEST(!Z3.I(A3_I));
+    TEST(isEqual(A3_I, Z3));
+    TEST(isEqual(A3.I(), Z3));
+
+    // cover NaN
+    A3(0, 0) = NAN;
+    A3(0, 1) = 0;
+    A3(0, 2) = 0;
+    A3_I = inv(A3);
+    TEST(isEqual(A3_I, Z3));
+    TEST(isEqual(A3.I(), Z3));
+
     return 0;
 }