diff --git a/internal/ceres/conditioned_cost_function_test.cc b/internal/ceres/conditioned_cost_function_test.cc
new file mode 100644
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+++ b/internal/ceres/conditioned_cost_function_test.cc
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+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+//   this list of conditions and the following disclaimer in the documentation
+//   and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+//   used to endorse or promote products derived from this software without
+//   specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: wjr@google.com (William Rucklidge)
+//
+// Tests for the conditioned cost function.
+
+#include "ceres/conditioned_cost_function.h"
+
+#include "gtest/gtest.h"
+#include "ceres/internal/eigen.h"
+#include "ceres/normal_prior.h"
+#include "ceres/types.h"
+
+namespace ceres {
+namespace internal {
+
+// The size of the cost functions we build.
+static const int kTestCostFunctionSize = 3;
+
+// A simple cost function: return ax + b.
+class LinearCostFunction : public CostFunction {
+ public:
+  LinearCostFunction(double a, double b) : a_(a), b_(b) {
+    set_num_residuals(1);
+    mutable_parameter_block_sizes()->push_back(1);
+  }
+
+  virtual bool Evaluate(double const* const* parameters,
+                        double* residuals,
+                        double** jacobians) const {
+    *residuals = **parameters * a_ + b_;
+    if (jacobians && *jacobians) {
+      **jacobians = a_;
+    }
+
+    return true;
+  }
+
+ private:
+  const double a_, b_;
+};
+
+// Tests that ConditionedCostFunction does what it's supposed to.
+TEST(CostFunctionTest, ConditionedCostFunction) {
+  double v1[kTestCostFunctionSize], v2[kTestCostFunctionSize],
+      jac[kTestCostFunctionSize * kTestCostFunctionSize],
+      result[kTestCostFunctionSize];
+
+  for (int i = 0; i < kTestCostFunctionSize; i++) {
+    v1[i] = i;
+    v2[i] = i * 10;
+    // Seed a few garbage values in the Jacobian matrix, to make sure that
+    // they're overwritten.
+    jac[i * 2] = i * i;
+    result[i] = i * i * i;
+  }
+
+  // Make a cost function that computes x - v2
+  VectorRef v2_vector(v2, kTestCostFunctionSize, 1);
+  Matrix identity(kTestCostFunctionSize, kTestCostFunctionSize);
+  identity.setIdentity();
+  NormalPrior* difference_cost_function = new NormalPrior(identity, v2_vector);
+
+  vector<CostFunction*> conditioners;
+  for (int i = 0; i < kTestCostFunctionSize; i++) {
+    conditioners.push_back(new LinearCostFunction(i + 2, i * 7));
+  }
+
+  ConditionedCostFunction conditioned_cost_function(difference_cost_function,
+                                                    conditioners,
+                                                    TAKE_OWNERSHIP);
+  EXPECT_EQ(difference_cost_function->num_residuals(),
+            conditioned_cost_function.num_residuals());
+  EXPECT_EQ(difference_cost_function->parameter_block_sizes(),
+            conditioned_cost_function.parameter_block_sizes());
+
+  double *parameters[1];
+  parameters[0] = v1;
+  double *jacs[1];
+  jacs[0] = jac;
+
+  conditioned_cost_function.Evaluate(parameters, result, jacs);
+  for (int i = 0; i < kTestCostFunctionSize; i++) {
+    EXPECT_DOUBLE_EQ((i + 2) * (v1[i] - v2[i]) + i * 7, result[i]);
+  }
+
+  for (int i = 0; i < kTestCostFunctionSize; i++) {
+    for (int j = 0; j < kTestCostFunctionSize; j++) {
+      double actual = jac[i * kTestCostFunctionSize + j];
+      if (i != j) {
+        EXPECT_DOUBLE_EQ(0, actual);
+      } else {
+        EXPECT_DOUBLE_EQ(i + 2, actual);
+      }
+    }
+  }
+}
+
+}  // namespace internal
+}  // namespace ceres