From e7b9a216b3111d92a798658f198216e567d0feeb Mon Sep 17 00:00:00 2001
From: CLIDragon <84266961+CLIDragon@users.noreply.github.com>
Date: Thu, 7 Nov 2024 17:59:01 +1000
Subject: [PATCH] Add tests for octile_dist_exact.

---
 tests/line_test.cpp | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tests/line_test.cpp b/tests/line_test.cpp
index 59f531570fee6..a12827f5c5b9b 100644
--- a/tests/line_test.cpp
+++ b/tests/line_test.cpp
@@ -465,3 +465,32 @@ TEST_CASE( "coord_point_line_to_consistency", "[point][coords][line]" )
         CHECK( raw_line[i] == coord_line[i].raw() );
     }
 }
+
+TEST_CASE("octile_dist_exact_tripoints") {
+    constexpr int one_axis = 1;
+    constexpr float two_axis = M_SQRT2;
+    constexpr float three_axis = 1.73205f;
+    constexpr float eps = 0.05f;
+
+    // Check that unit distances are all correct.
+    CHECK(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 0, 0, 0 }) == 0);
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 0, 0, 1 }), Catch::Matchers::WithinRel(1, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 0, 1, 0 }), Catch::Matchers::WithinRel(1, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 1, 0, 0 }), Catch::Matchers::WithinRel(1, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 10 , 30, 20 }, tripoint{ 11, 30, 20 }), Catch::Matchers::WithinRel(1, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 10 , 30, 20 }, tripoint{ 10, 31, 20 }), Catch::Matchers::WithinRel(1, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 10 , 30, 21 }, tripoint{ 10, 30, 21 }), Catch::Matchers::WithinRel(1, eps));
+
+    // Check that 2d unit distances are correct.
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 0, 1, 1 }), Catch::Matchers::WithinRel(two_axis, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 1, 0, 1 }), Catch::Matchers::WithinRel(two_axis, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 1, 1, 0 }), Catch::Matchers::WithinRel(two_axis, eps));
+
+    // Check that 3d unit distances are correct.
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 1, 1, 1 }), Catch::Matchers::WithinRel(three_axis, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 2 , 4, 6 }, tripoint{ 3, 5, 7 }), Catch::Matchers::WithinRel(three_axis, eps));
+    CHECK_THAT(octile_dist_exact(tripoint{ 26 , 32, 75 }, tripoint{ 27, 33, 76 }), Catch::Matchers::WithinRel(three_axis, eps));
+
+    // Check a few non-unit distances.
+    CHECK_THAT(octile_dist_exact(tripoint{ 0 , 0, 0 }, tripoint{ 2, 2, 0 }), Catch::Matchers::WithinRel(2 * two_axis, eps));
+}