diff --git a/Userland/Libraries/LibTest/Macros.h b/Userland/Libraries/LibTest/Macros.h
index 004154ee3e7..5f2f3cdd243 100644
--- a/Userland/Libraries/LibTest/Macros.h
+++ b/Userland/Libraries/LibTest/Macros.h
@@ -109,6 +109,25 @@ void disable_reporting();
 
 #define EXPECT_APPROXIMATE(a, b) EXPECT_APPROXIMATE_WITH_ERROR(a, b, 0.0000005)
 
+#define REJECT(message)                                                \
+    do {                                                               \
+        if (::Test::is_reporting_enabled())                            \
+            ::AK::warnln("\033[31;1mREJECTED\033[0m: {}:{}: {}",       \
+                __FILE__, __LINE__, #message);                         \
+        ::Test::set_current_test_result(::Test::TestResult::Rejected); \
+    } while (false)
+
+#define ASSUME(x)                                                                                                      \
+    do {                                                                                                               \
+        if (!(x)) {                                                                                                    \
+            if (::Test::is_reporting_enabled())                                                                        \
+                ::AK::warnln("\033[31;1mREJECTED\033[0m: {}:{}: Couldn't generate random value satisfying ASSUME({})", \
+                    __FILE__, __LINE__, #x);                                                                           \
+            ::Test::set_current_test_result(::Test::TestResult::Rejected);                                             \
+            return;                                                                                                    \
+        }                                                                                                              \
+    } while (false)
+
 #define FAIL(message)                                                                      \
     do {                                                                                   \
         if (::Test::is_reporting_enabled())                                                \
diff --git a/Userland/Libraries/LibTest/TestResult.h b/Userland/Libraries/LibTest/TestResult.h
index d63b763800f..513a60e5d57 100644
--- a/Userland/Libraries/LibTest/TestResult.h
+++ b/Userland/Libraries/LibTest/TestResult.h
@@ -18,6 +18,11 @@ enum class TestResult {
     // Didn't get through EXPECT(...).
     Failed,
 
+    // Didn't get through the ASSUME(...) filter 15 times in a row
+    // (in a randomized test).
+    // Alternatively, user used REJECT(...).
+    Rejected,
+
     // Ran out of RandomRun data (in a randomized test, when shrinking).
     // This is fine, we'll just try some other shrink.
     Overrun,
diff --git a/Userland/Libraries/LibTest/TestSuite.cpp b/Userland/Libraries/LibTest/TestSuite.cpp
index 76076de110b..53cd499932c 100644
--- a/Userland/Libraries/LibTest/TestSuite.cpp
+++ b/Userland/Libraries/LibTest/TestSuite.cpp
@@ -103,6 +103,8 @@ static DeprecatedString test_result_to_string(TestResult result)
         return "Completed";
     case TestResult::Failed:
         return "Failed";
+    case TestResult::Rejected:
+        return "Rejected";
     case TestResult::Overrun:
         return "Ran out of randomness";
     default: