From cd1dd2037cbe1d5f1362202d3127640406b468b8 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 13 Apr 2026 15:38:08 +0200
Subject: kstd: add basic format and format_to tests

---
 libs/kstd/tests/src/format.cpp | 116 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 libs/kstd/tests/src/format.cpp

(limited to 'libs/kstd/tests')

diff --git a/libs/kstd/tests/src/format.cpp b/libs/kstd/tests/src/format.cpp
new file mode 100644
index 0000000..4915e50
--- /dev/null
+++ b/libs/kstd/tests/src/format.cpp
@@ -0,0 +1,116 @@
+#include <kstd/flat_map>
+#include <kstd/format>
+#include <kstd/tests/os_panic.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <iterator>
+#include <sstream>
+
+SCENARIO("Formatting to a new string", "[format]")
+{
+  GIVEN("a format string without any placeholders")
+  {
+    auto const & fmt = "This is a test";
+
+    WHEN("calling format with without any arguments.")
+    {
+      auto result = kstd::format(fmt);
+
+      THEN("the result is the unmodified string")
+      {
+        REQUIRE(result == "This is a test");
+      }
+    }
+
+    WHEN("calling format with additional arguments")
+    {
+      auto result = kstd::format(fmt, 1, 2, 3);
+
+      THEN("the result is the unmodified string")
+      {
+        REQUIRE(result == "This is a test");
+      }
+    }
+  }
+
+  GIVEN("a format string with placeholders")
+  {
+    auto const & fmt = "Here are some placeholders: {} {} {}";
+
+    WHEN("calling format with the same number of arguments as there are placeholders")
+    {
+      auto result = kstd::format(fmt, 1, true, -100);
+
+      THEN("the result is the formatted string")
+      {
+        REQUIRE(result == "Here are some placeholders: 1 true -100");
+      }
+    }
+
+    WHEN("calling format with too many arguments")
+    {
+      auto result = kstd::format(fmt, 2, false, -200, 4, 5, 6);
+
+      THEN("the result is the formatted string")
+      {
+        REQUIRE(result == "Here are some placeholders: 2 false -200");
+      }
+    }
+  }
+}
+
+SCENARIO("Formatting to an output iterator", "[format]")
+{
+  auto buffer = std::ostringstream{};
+
+  GIVEN("a format string without any placeholders")
+  {
+    auto const & fmt = "This is a test";
+
+    WHEN("calling format with without any arguments.")
+    {
+      kstd::format_to(std::ostream_iterator<char>{buffer}, fmt);
+
+      THEN("the unmodified string is written to the iterator")
+      {
+        REQUIRE(buffer.str() == "This is a test");
+      }
+    }
+
+    WHEN("calling format with additional arguments")
+    {
+      kstd::format_to(std::ostream_iterator<char>{buffer}, fmt, 1, 2, 3);
+
+      THEN("the unmodified string is written to the iterator")
+      {
+        REQUIRE(buffer.str() == "This is a test");
+      }
+    }
+  }
+
+  GIVEN("a format string with placeholders")
+  {
+    auto const & fmt = "Here are some placeholders: {} {} {}";
+
+    WHEN("calling format with the same number of arguments as there are placeholders")
+    {
+      kstd::format_to(std::ostream_iterator<char>{buffer}, fmt, 1, true, -100);
+
+      THEN("the formatted string is written to the iterator")
+      {
+        REQUIRE(buffer.str() == "Here are some placeholders: 1 true -100");
+      }
+    }
+
+    WHEN("calling format with too many arguments")
+    {
+      kstd::format_to(std::ostream_iterator<char>{buffer}, fmt, 2, false, -200, 4, 5, 6);
+
+      THEN("the formatted string is written to the iterator")
+      {
+        REQUIRE(buffer.str() == "Here are some placeholders: 2 false -200");
+      }
+    }
+  }
+}
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