Faster selection of tests to run

Similar to the change that removed `std::set` from the test registration
path, this saves an allocation per test to run, and is faster to boot.

Technically, the performance of selecting tests for multiple OR-joined
filters, each of which selects many (most) tests is a bit slower,
but that is not very common use case.

1 files changed, 13 insertions, 6 deletions

diff --git a/src/catch2/catch_session.cpp b/src/catch2/catch_session.cpp
index 503da14f..78cb5a06 100644
--- a/src/catch2/catch_session.cpp
+++ b/src/catch2/catch_session.cpp
@@ -31,7 +31,6 @@
 #include <cstdlib>
 #include <exception>
 #include <iomanip>
-#include <set>
 
 namespace Catch {
 
@@ -86,21 +85,29 @@ namespace Catch {
                 assert( m_config->testSpec().getInvalidSpecs().empty() &&
                         "Invalid test specs should be handled before running tests" );
 
+                // Note that we are working with pointers into this vector
+                // of sorted test cases, so sorting/unique-ing the pointers
+                // keeps the user-specified order.
                 auto const& allTestCases = getAllTestCasesSorted(*m_config);
                 auto const& testSpec = m_config->testSpec();
+                m_tests.reserve( allTestCases.size() );
                 if ( !testSpec.hasFilters() ) {
                     for ( auto const& test : allTestCases ) {
                         if ( !test.getTestCaseInfo().isHidden() ) {
-                            m_tests.emplace( &test );
+                            m_tests.push_back( &test );
                         }
                     }
                 } else {
-                    m_matches =
-                        testSpec.matchesByFilter( allTestCases, *m_config );
+                    m_matches = testSpec.matchesByFilter( allTestCases, *m_config );
                     for ( auto const& match : m_matches ) {
-                        m_tests.insert( match.tests.begin(),
+                        m_tests.insert( m_tests.end(),
+                                        match.tests.begin(),
                                         match.tests.end() );
                     }
+                    std::sort( m_tests.begin(), m_tests.end() );
+                    m_tests.erase(
+                        std::unique( m_tests.begin(), m_tests.end() ),
+                        m_tests.end() );
                 }
 
                 m_tests = createShard(CATCH_MOVE(m_tests), m_config->shardCount(), m_config->shardIndex());
@@ -134,7 +141,7 @@ namespace Catch {
             IEventListener* m_reporter;
             Config const* m_config;
             RunContext m_context;
-            std::set<TestCaseHandle const*> m_tests;
+            std::vector<TestCaseHandle const*> m_tests;
             TestSpec::Matches m_matches;
             bool m_unmatchedTestSpecs = false;
         };