diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index fa593e24..4d9b4a8e 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -141,4 +141,5 @@ run exception/move_assign_exception_tests.cpp : : : <cxxstd>98:<build>no <cxxstd
 run exception/insert_exception_tests.cpp : : : <cxxstd>98:<build>no <cxxstd>03:<build>no <cxxstd>0x:<build>no <define>BOOST_UNORDERED_FOA_TESTS : foa_insert_exception_tests ;
 run exception/erase_exception_tests.cpp : : : <cxxstd>98:<build>no <cxxstd>03:<build>no <cxxstd>0x:<build>no <define>BOOST_UNORDERED_FOA_TESTS : foa_erase_exception_tests ;
 run exception/rehash_exception_tests.cpp : : : <cxxstd>98:<build>no <cxxstd>03:<build>no <cxxstd>0x:<build>no <define>BOOST_UNORDERED_FOA_TESTS : foa_rehash_exception_tests ;
+run exception/swap_exception_tests.cpp : : : <cxxstd>98:<build>no <cxxstd>03:<build>no <cxxstd>0x:<build>no <define>BOOST_UNORDERED_FOA_TESTS : foa_swap_exception_tests ;
 run exception/merge_exception_tests.cpp : : : <cxxstd>98:<build>no <cxxstd>03:<build>no <cxxstd>0x:<build>no <define>BOOST_UNORDERED_FOA_TESTS : foa_merge_exception_tests ;
diff --git a/test/exception/swap_exception_tests.cpp b/test/exception/swap_exception_tests.cpp
index 1569e814..2745ede5 100644
--- a/test/exception/swap_exception_tests.cpp
+++ b/test/exception/swap_exception_tests.cpp
@@ -5,6 +5,10 @@
 
 #include "./containers.hpp"
 
+#if defined(BOOST_UNORDERED_FOA_TESTS)
+#define BOOST_UNORDERED_FOA_WEAK_GUARANTEE_SWAP_EXCEPTIONS_TESTS
+#endif
+
 #include "../helpers/invariants.hpp"
 #include "../helpers/random_values.hpp"
 #include "../helpers/tracker.hpp"
diff --git a/test/helpers/invariants.hpp b/test/helpers/invariants.hpp
index 3a4ddedf..849fe983 100644
--- a/test/helpers/invariants.hpp
+++ b/test/helpers/invariants.hpp
@@ -53,10 +53,20 @@ namespace test {
       if (test::has_unique_keys<X>::value && count != 1)
         BOOST_ERROR("Non-unique key.");
 
+#if !defined(BOOST_UNORDERED_FOA_WEAK_GUARANTEE_SWAP_EXCEPTIONS_TESTS)
+      // we conditionally compile this check because our FOA implementation only
+      // exhibits the weak guarantee when swapping throws
+      //
+      // in this case, the hasher may be changed before the predicate and the
+      // arrays are swapped in which case, we can can find an element by
+      // iteration but unfortunately, it's in the wrong slot according to the
+      // new hash function so count(key) can wind up returning nothing when
+      // there really is something
       if (x1.count(key) != count) {
         BOOST_ERROR("Incorrect output of count.");
         std::cerr << x1.count(key) << "," << count << "\n";
       }
+#endif
 
 #ifndef BOOST_UNORDERED_FOA_TESTS
       // Check that the keys are in the correct bucket and are