Give Catch3 its own build names and headers

Catch2 compatibility means the API tests are written in: the macros, such
as TEST_CASE and REQUIRE, and the Catch:: namespace. It does not mean
Catch2's build names or header paths. find_package(Catch2) found Catch3,
and a project using both frameworks met two packages, two sets of targets,
two Catch.cmake modules and two catch2/ header trees with the same names.

Build names:
- CMake: project and package Catch3, targets Catch3::Catch3 and
  Catch3::Catch3WithMain, libraries Catch3 and Catch3Main, options
  CATCH3_*, lib/cmake/Catch3 with Catch3Config, and pkg-config catch3 and
  catch3-with-main. The version is Catch3's, 0.3.0, compatible within a
  minor version.
- The CMake scripts are Catch3.cmake (catch3_discover_tests),
  Catch3AddTests.cmake and Catch3ShardTests.cmake
  (catch3_add_sharded_tests); the helpers they define at ctest time have a
  catch3_ prefix. ParseAndAddCatchTests.cmake, deprecated upstream, is gone.
- Bazel //:catch3 and //:catch3_main, Meson catch3 and catch3-with-main
  (with override_dependency), Xmake catch3 and catch3_main, Premake Catch3
  and Catch3WithMain. Visual Studio projects get GUIDs of their own.
- The Progmasoft::Catch3 target and package are gone: property testing
  and snapshots are part of Catch3::Catch3. Their sources now build with
  the library's warning flags, so property failures are built field by
  field (no missing initializers) and the default property name is a
  thread-local pointer to the name its scope owns (no global destructor).

Headers: the engine moved from src/catch2 to src/Progmasoft/Catch3 with
Progmasoft names, so <catch2/catch_test_macros.hpp> is
<Progmasoft/Catch3/TestMacros.hpp>, <catch2/matchers/catch_matchers_string.hpp>
is <Progmasoft/Catch3/Matchers/String.hpp>, and interface headers are named
after their interface, such as Interfaces/IConfig.hpp. Include guards
became #pragma once. The installed headers go to include/Progmasoft.
src/Progmasoft/Context.cpp is StrategyContext.cpp, so no two sources share
a file name.

tools/scripts/upstreamFiles.txt lists the files that come from Catch2.
The license check expects BSL-1.0 on them and Progmasoft's header on the
rest of src/Progmasoft; the convenience-header check, the amalgamation
script and the surrogate tests take the engine's headers from it. The
amalgamated files are regenerated. The header-guard workflow checks for
#pragma once instead of checkguard.

Documents, the README and the release notes describe the new names.

1 files changed, 85 insertions, 0 deletions

diff --git a/src/Progmasoft/Catch3/Approx.cpp b/src/Progmasoft/Catch3/Approx.cpp
new file mode 100644
index 00000000..aafbc316
--- /dev/null
+++ b/src/Progmasoft/Catch3/Approx.cpp
@@ -0,0 +1,85 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#include <Progmasoft/Catch3/Approx.hpp>
+#include <Progmasoft/Catch3/Internal/Enforce.hpp>
+#include <Progmasoft/Catch3/Internal/ReusableStringStream.hpp>
+
+#include <cmath>
+#include <limits>
+
+namespace {
+
+// Performs equivalent check of std::fabs(lhs - rhs) <= margin
+// But without the subtraction to allow for INFINITY in comparison
+bool marginComparison(double lhs, double rhs, double margin) {
+    return (lhs + margin >= rhs) && (rhs + margin >= lhs);
+}
+
+}
+
+namespace Catch {
+
+    Approx::Approx ( double value )
+    :   m_epsilon( static_cast<double>(std::numeric_limits<float>::epsilon())*100. ),
+        m_margin( 0.0 ),
+        m_scale( 0.0 ),
+        m_value( value )
+    {}
+
+    Approx Approx::custom() {
+        return Approx( 0 );
+    }
+
+    Approx Approx::operator-() const {
+        auto temp(*this);
+        temp.m_value = -temp.m_value;
+        return temp;
+    }
+
+
+    std::string Approx::toString() const {
+        ReusableStringStream rss;
+        rss << "Approx( " << ::Catch::Detail::stringify( m_value ) << " )";
+        return rss.str();
+    }
+
+    bool Approx::equalityComparisonImpl(const double other) const {
+        // First try with fixed margin, then compute margin based on epsilon, scale and Approx's value
+        // Thanks to Richard Harris for his help refining the scaled margin value
+        return marginComparison(m_value, other, m_margin)
+            || marginComparison(m_value, other, m_epsilon * (m_scale + std::fabs(std::isinf(m_value)? 0 : m_value)));
+    }
+
+    void Approx::setMargin(double newMargin) {
+        CATCH_ENFORCE(newMargin >= 0,
+            "Invalid Approx::margin: " << newMargin << '.'
+            << " Approx::Margin has to be non-negative.");
+        m_margin = newMargin;
+    }
+
+    void Approx::setEpsilon(double newEpsilon) {
+        CATCH_ENFORCE(newEpsilon >= 0 && newEpsilon <= 1.0,
+            "Invalid Approx::epsilon: " << newEpsilon << '.'
+            << " Approx::epsilon has to be in [0, 1]");
+        m_epsilon = newEpsilon;
+    }
+
+namespace literals {
+    Approx operator ""_a(long double val) {
+        return Approx(val);
+    }
+    Approx operator ""_a(unsigned long long val) {
+        return Approx(val);
+    }
+} // end namespace literals
+
+std::string StringMaker<Catch::Approx>::convert(Catch::Approx const& value) {
+    return value.toString();
+}
+
+} // end namespace Catch