From 527070b89cb896290e117be32ce2d79d96146849 Mon Sep 17 00:00:00 2001
From: ggould-tri <ggould@tri.global>
Date: Tue, 8 Dec 2020 10:23:50 -0500
Subject: [PATCH] Separate out the unit test for the degenerate case

 * This is a trivial disturbance to the test to correct
   a spurious kcov error; see
   https://github.com/SimonKagstrom/kcov/issues/339
 * Closes #14424
---
 math/test/gray_code_test.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/math/test/gray_code_test.cc b/math/test/gray_code_test.cc
index 047f52444998..4e198553fed7 100644
--- a/math/test/gray_code_test.cc
+++ b/math/test/gray_code_test.cc
@@ -7,8 +7,15 @@
 namespace drake {
 namespace math {
 namespace {
+
+GTEST_TEST(TestGrayCode, TestDegenerateCase) {
+  auto zero_code = CalculateReflectedGrayCodes(0);
+  EXPECT_EQ(zero_code.cols(), 0);
+  EXPECT_EQ(zero_code.rows(), 0);
+}
+
 GTEST_TEST(TestGrayCode, TestCalculateGrayCodes) {
-  for (int i = 0; i < 4; i++) {
+  for (int i = 1; i < 4; i++) {
     auto test_code = CalculateReflectedGrayCodes(i);
     // Asking for codes for 0 bits should generate 0 for 0 bits.
     // Asking for codes for i bits should generate 2^(i) codes for i bits.