Tests: add unit test coverage for NumberUtils::from_chars directly

Currently it was only tested indirectly via XMLReaderUtils_tests and
file format tests

Signed-off-by: Aras Pranckevicius <[email protected]>

Author: aras-p

tests/utils/CMakeLists.txt

@@ -5,6 +5,7 @@ include(ExternalProject)
 
 set(SOURCES
     UnitTestMain.cpp
+    NumberUtils_tests.cpp
     StringUtils_tests.cpp
 )
 

tests/utils/NumberUtils_tests.cpp

@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright Contributors to the OpenColorIO Project.
+
+
+#include "testutils/UnitTest.h"
+#include "utils/NumberUtils.h"
+
+namespace OCIO = OCIO_NAMESPACE;
+
+OCIO_ADD_TEST(NumberUtils, from_chars_float)
+{
+#define TEST_FROM_CHARS(text) \
+    str = text; \
+    res = OCIO::NumberUtils::from_chars(str.data(), str.data() + str.size(), val); \
+    OCIO_CHECK_ASSERT(res.ec == std::errc()); \
+    OCIO_CHECK_ASSERT(res.ptr == str.data() + str.size())
+
+    std::string str;
+    float val;
+    OCIO::NumberUtils::from_chars_result res;
+
+    // regular numbers
+    TEST_FROM_CHARS("-7"); OCIO_CHECK_EQUAL(val, -7.0f);
+    TEST_FROM_CHARS("1.5"); OCIO_CHECK_EQUAL(val, 1.5f);
+    TEST_FROM_CHARS("-17.25"); OCIO_CHECK_EQUAL(val, -17.25f);
+    TEST_FROM_CHARS("-.75"); OCIO_CHECK_EQUAL(val, -.75f);
+    TEST_FROM_CHARS("11."); OCIO_CHECK_EQUAL(val, 11.0f);
+    // exponent notation
+    TEST_FROM_CHARS("1e3"); OCIO_CHECK_EQUAL(val, 1000.0f);
+    TEST_FROM_CHARS("1e+2"); OCIO_CHECK_EQUAL(val, 100.0f);
+    TEST_FROM_CHARS("50e-2"); OCIO_CHECK_EQUAL(val, 0.5f);
+    TEST_FROM_CHARS("-1.5e2"); OCIO_CHECK_EQUAL(val, -150.0f);
+    // whitespace/prefix handling
+    TEST_FROM_CHARS("+57.125"); OCIO_CHECK_EQUAL(val, +57.125f);
+    TEST_FROM_CHARS("  \t 123.5"); OCIO_CHECK_EQUAL(val, 123.5f);
+    // special values
+    TEST_FROM_CHARS("-infinity"); OCIO_CHECK_EQUAL(val, -std::numeric_limits<float>::infinity());
+    TEST_FROM_CHARS("nan"); OCIO_CHECK_ASSERT(std::isnan(val));
+    // hex format should be parsed
+    TEST_FROM_CHARS("0x42"); OCIO_CHECK_EQUAL(val, 66.0f);
+    TEST_FROM_CHARS("0x42ab.c"); OCIO_CHECK_EQUAL(val, 17067.75f);
+
+    // valid numbers with trailing non-number chars should stop there
+    str = "-7.5ab";
+    res = OCIO::NumberUtils::from_chars(str.data(), str.data() + str.size(), val);
+    OCIO_CHECK_ASSERT(res.ptr == str.data() + 4);
+    OCIO_CHECK_EQUAL(val, -7.5f);
+    str = "infinitya";
+    res = OCIO::NumberUtils::from_chars(str.data(), str.data() + str.size(), val);
+    OCIO_CHECK_ASSERT(res.ptr == str.data() + 8);
+    OCIO_CHECK_EQUAL(val, std::numeric_limits<float>::infinity());
+    str = "0x18g";
+    res = OCIO::NumberUtils::from_chars(str.data(), str.data() + str.size(), val);
+    OCIO_CHECK_ASSERT(res.ptr == str.data() + 4);
+    OCIO_CHECK_EQUAL(val, 24.0f);
+
+#undef TEST_FROM_CHARS
+}
+
+OCIO_ADD_TEST(NumberUtils, from_chars_float_failures)
+{
+#define TEST_FROM_CHARS(text) \
+    str = text; \
+    res = OCIO::NumberUtils::from_chars(str.data(), str.data() + str.size(), val); \
+    OCIO_CHECK_EQUAL(val, 7.5f); \
+    OCIO_CHECK_ASSERT(res.ec == std::errc::invalid_argument)
+
+    std::string str;
+    float val = 7.5f;
+    OCIO::NumberUtils::from_chars_result res;
+
+    TEST_FROM_CHARS("");
+    TEST_FROM_CHARS("ab");
+    TEST_FROM_CHARS("   ");
+    TEST_FROM_CHARS("---");
+    TEST_FROM_CHARS("e3");
+    TEST_FROM_CHARS("_x");
+    TEST_FROM_CHARS("+.");
+
+#undef TEST_FROM_CHARS
+}