2 files changed, 180 insertions, 1 deletions
diff --git a/source/test/unittests/CMakeLists.txt b/source/test/unittests/CMakeLists.txt
index ff99c9c..75b1f3f 100644
--- a/source/test/unittests/CMakeLists.txt
+++ b/source/test/unittests/CMakeLists.txt
@@ -2,4 +2,5 @@ target_sources(
   ${KIT_TEST_SUITE}
     PRIVATE
       async_function.test.c main.test.c array_ref.test.c
-      input_stream.test.c input_buffer.test.c dynamic_array.test.c)
+      input_stream.test.c lower_bound.test.c input_buffer.test.c
+      dynamic_array.test.c)
diff --git a/source/test/unittests/lower_bound.test.c b/source/test/unittests/lower_bound.test.c
new file mode 100644
index 0000000..275acd6
--- /dev/null
+++ b/source/test/unittests/lower_bound.test.c
@@ -0,0 +1,178 @@
+#include "../../kit/lower_bound.h"
+#include "../../kit/array_ref.h"
+
+#define KIT_TEST_FILE lower_bound
+#include "../../kit_test/test.h"
+
+static int kit_less_int(int left, int right) {
+  return left < right;
+}
+
+static int kit_less_int_ref(int const *left, int const *right) {
+  return *left < *right;
+}
+
+TEST("lower bound empty") {
+  AR_CONST(ref, int) = { .size = 0, .values = NULL };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 42, kit_less_int);
+  REQUIRE(index == 0);
+}
+
+TEST("lower bound single left") {
+  int const v[1]     = { 42 };
+  AR_CONST(ref, int) = { .size = 1, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 42, kit_less_int);
+  REQUIRE(index == 0);
+}
+
+TEST("lower bound single right") {
+  int const v[1]     = { 42 };
+  AR_CONST(ref, int) = { .size = 1, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 43, kit_less_int);
+  REQUIRE(index == 1);
+}
+
+TEST("lower bound first of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 1, kit_less_int);
+  REQUIRE(index == 0);
+}
+
+TEST("lower bound second of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 2, kit_less_int);
+  REQUIRE(index == 1);
+}
+
+TEST("lower bound third of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 3, kit_less_int);
+  REQUIRE(index == 2);
+}
+
+TEST("lower bound forth of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 4, kit_less_int);
+  REQUIRE(index == 3);
+}
+
+TEST("lower bound fifth of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 5, kit_less_int);
+  REQUIRE(index == 4);
+}
+
+TEST("lower bound first of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 1, kit_less_int);
+  REQUIRE(index == 0);
+}
+
+TEST("lower bound second of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 2, kit_less_int);
+  REQUIRE(index == 1);
+}
+
+TEST("lower bound third of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 3, kit_less_int);
+  REQUIRE(index == 2);
+}
+
+TEST("lower bound forth of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 4, kit_less_int);
+  REQUIRE(index == 3);
+}
+
+TEST("lower bound fifth of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 5, kit_less_int);
+  REQUIRE(index == 4);
+}
+
+TEST("lower bound sixth of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND(index, ref, 6, kit_less_int);
+  REQUIRE(index == 5);
+}
+
+TEST("lower bound ref first of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  int const value    = 1;
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND_REF(index, ref, value, kit_less_int_ref);
+  REQUIRE(index == 0);
+}
+
+TEST("lower bound ref second of four") {
+  int const v[4]     = { 1, 2, 3, 4 };
+  int const value    = 2;
+  AR_CONST(ref, int) = { .size = 4, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND_REF(index, ref, value, kit_less_int_ref);
+  REQUIRE(index == 1);
+}
+
+TEST("lower bound ref fifth of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  int const value    = 5;
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND_REF(index, ref, value, kit_less_int_ref);
+  REQUIRE(index == 4);
+}
+
+TEST("lower bound ref sixth of five") {
+  int const v[5]     = { 1, 2, 3, 4, 5 };
+  int const value    = 6;
+  AR_CONST(ref, int) = { .size = 5, .values = v };
+
+  ptrdiff_t index;
+  KIT_LOWER_BOUND_REF(index, ref, value, kit_less_int_ref);
+  REQUIRE(index == 5);
+}