diff --git a/tests/FrameCameraTests.cpp b/tests/FrameCameraTests.cpp
index 976e90e3aa38a1486638fc3adade02278287fd74..31fd953646f4f77d240218d3c5b22ee31011f267 100644
--- a/tests/FrameCameraTests.cpp
+++ b/tests/FrameCameraTests.cpp
@@ -79,6 +79,14 @@ TEST_F(FrameSensorModel, getImageIdentifier) {
   EXPECT_EQ("simpleFramerISD", sensorModel->getImageIdentifier());
 }
 
+TEST_F(FrameSensorModel, Inversion) {
+   csm::ImageCoord imagePt1(9.0, 9.0);
+   csm::EcefCoord groundPt = sensorModel->imageToGround(imagePt1, 0.0);
+   csm::ImageCoord imagePt2 = sensorModel->groundToImage(groundPt);
+   EXPECT_DOUBLE_EQ(imagePt1.line, imagePt2.line);
+   EXPECT_DOUBLE_EQ(imagePt1.samp, imagePt2.samp);
+}
+
 TEST_F(OrbitalFrameSensorModel, Center) {
    csm::ImageCoord imagePt(8.0, 8.0);
    csm::EcefCoord groundPt = sensorModel->imageToGround(imagePt, 0.0);
diff --git a/tests/UtilitiesTests.cpp b/tests/UtilitiesTests.cpp
index 549b9c09d78d69b017c24e9bca7b0833fdbbf387..4da9a089000541e8e7eac2b2b6d92d5882468a82 100644
--- a/tests/UtilitiesTests.cpp
+++ b/tests/UtilitiesTests.cpp
@@ -141,6 +141,21 @@ TEST(UtilitiesTests, computePixelStart) {
    EXPECT_DOUBLE_EQ(sample, 4.0);
 }
 
+TEST(UtilitiesTests, computePixelStartSumming) {
+   double iTransS[] = {0.0, 0.0, 10.0};
+   double iTransL[] = {0.0, 10.0, 0.0};
+   double line, sample;
+   computePixel(
+         -0.5, -0.2,
+         8.0, 8.0,
+         2.0, 4.0,
+         2.0, 1.0,
+         iTransS, iTransL,
+         line, sample);
+   EXPECT_DOUBLE_EQ(line, 0.5);
+   EXPECT_DOUBLE_EQ(sample, 2.0);
+}
+
 TEST(UtilitiesTests, createCameraLookVector) {
   double cameraLook[3];
   createCameraLookVector(0, -0.4, 1, 50, cameraLook);