diff --git a/CHANGES b/CHANGES
index 96d32960ec..5fc112f432 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,26 @@
+6.1.0-dev.42 | 2023-06-14 12:51:08 +0200
+
+  * NEWS: Small section about assert statement (Arne Welzel, Corelight)
+
+  * Stmt: Rework assertion hooks break semantics (Arne Welzel, Corelight)
+
+    Using break in either of the hooks allows to suppress the default reporter
+    error message rather than suppressing solely based on the existence of an
+    assertion_failure() handler.
+
+  * Stmt: Introduce assert statement and related hooks (Arne Welzel, Corelight)
+
+    including two hooks called assertion_failure() and assertion_result() for
+    customization and tracking of assertion results.
+
+  * ZeekArgs: Helper for empty arguments (Arne Welzel, Corelight)
+
+  * Reporter: Allow AssertStmt to throw InterpreterException (Arne Welzel, Corelight)
+
+  * Lift backtrace() code into Func.{h,cc} (Arne Welzel, Corelight)
+
+    This is to be re-used by the assertion facility.
+
 6.1.0-dev.32 | 2023-06-13 11:29:36 -0700
 
   * Clarify subitem relationship in CMake configure summary. (Benjamin Bannier, Corelight)
diff --git a/NEWS b/NEWS
index b6ca019137..4a4bd94e08 100644
--- a/NEWS
+++ b/NEWS
@@ -9,9 +9,28 @@ Zeek 6.1.0
 Breaking Changes
 ----------------
 
+* ``assert`` is now a reserved keyword for the new ``assert`` statement.
+
 New Functionality
 -----------------
 
+- Added a new ``assert`` statement for assertion based testing and asserting
+  runtime state.
+
+	assert <expr: bool>[, <message: string>];
+
+  This statement comes with two hooks. First, ``assertion_failure()`` that
+  is invoked for every failing assert statement. Second, ``assertion_result()``
+  which is invoked for every assert statement and its outcome. The latter allows
+  to construct a summary of failing and passing assert statements. Both hooks
+  receive the location and call stack for the ``assert`` statement via a
+  ``Backtrace`` vector.
+
+  A failing assert will abort execution of the current event handler similar
+  to scripting errors. By default, a reporter error message is logged. Using
+  the break statement within ``assertion_failure()`` or ``assertion_result()``
+  allows to suppress the default message.
+
 Changed Functionality
 ---------------------
 
diff --git a/VERSION b/VERSION
index 36cfa15110..8a8455a4b8 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-6.1.0-dev.32
+6.1.0-dev.42
diff --git a/scripts/base/init-bare.zeek b/scripts/base/init-bare.zeek
index fb15bea8dd..ec809377de 100644
--- a/scripts/base/init-bare.zeek
+++ b/scripts/base/init-bare.zeek
@@ -942,6 +942,45 @@ type BacktraceElement: record {
 ## .. zeek:see:: backtrace print_backtrace
 type Backtrace: vector of BacktraceElement;
 
+## A hook that is invoked when an assert statement fails.
+##
+## By default, a reporter error message is logged describing the failing
+## assert similarly to how scripting errors are reported after invoking
+## this hook. Using the :zeek:see:`break` statement in an assertion_failure
+## hook handler allows to suppress this message.
+##
+## cond: The string representation of the condition.
+##
+## msg: Evaluated message as string given to the assert statement.
+##
+## bt: Backtrace of the assertion error. The top element will contain
+##     the location of the assert statement that failed.
+##
+## .. zeek:see:: assertion_result
+type assertion_failure: hook(cond: string, msg: string, bt: Backtrace);
+
+## A hook that is invoked with the result of every assert statement.
+##
+## This is a potentially expensive hook meant to be used by testing
+## frameworks to summarize assert results. In a production setup,
+## this hook is likely detrimental to performance.
+##
+## Using the :zeek:see:`break` statement within an assertion_failure hook
+## handler allows to suppress the reporter error message generated for
+## failing assert statements.
+##
+## result: The result of evaluating **cond**.
+##
+## cond: The string representation of the condition.
+##
+## msg: Evaluated message as string given to the assert statement.
+##
+## bt: Backtrace of the assertion error. The top element will contain
+##     the location of the assert statement that failed.
+##
+## .. zeek:see:: assertion_failure
+type assertion_result: hook(result: bool, cond: string, msg: string, bt: Backtrace);
+
 # todo:: Do we still need these here? Can they move into the packet filter
 # framework?
 #
diff --git a/src/Func.cc b/src/Func.cc
index f56719ee00..fa08d81709 100644
--- a/src/Func.cc
+++ b/src/Func.cc
@@ -903,6 +903,59 @@ FunctionIngredients::FunctionIngredients(ScopePtr _scope, StmtPtr _body,
 		}
 	}
 
+zeek::RecordValPtr make_backtrace_element(std::string_view name, const VectorValPtr args,
+                                          const zeek::detail::Location* loc)
+	{
+	static auto elem_type = id::find_type<RecordType>("BacktraceElement");
+	static auto function_name_idx = elem_type->FieldOffset("function_name");
+	static auto function_args_idx = elem_type->FieldOffset("function_args");
+	static auto file_location_idx = elem_type->FieldOffset("file_location");
+	static auto line_location_idx = elem_type->FieldOffset("line_location");
+
+	auto elem = make_intrusive<RecordVal>(elem_type);
+	elem->Assign(function_name_idx, name.data());
+	elem->Assign(function_args_idx, std::move(args));
+
+	if ( loc )
+		{
+		elem->Assign(file_location_idx, loc->filename);
+		elem->Assign(line_location_idx, loc->first_line);
+		}
+
+	return elem;
+	}
+
+zeek::VectorValPtr get_current_script_backtrace()
+	{
+	static auto backtrace_type = id::find_type<VectorType>("Backtrace");
+
+	auto rval = make_intrusive<VectorVal>(backtrace_type);
+
+	// The body of the following loop can wind up adding items to
+	// the call stack (because MakeCallArgumentVector() evaluates
+	// default arguments, which can in turn involve calls to script
+	// functions), so we work from a copy of the current call stack
+	// to prevent problems with iterator invalidation.
+	auto cs_copy = zeek::detail::call_stack;
+
+	for ( auto it = cs_copy.rbegin(); it != cs_copy.rend(); ++it )
+		{
+		const auto& ci = *it;
+		if ( ! ci.func )
+			// This happens for compiled code.
+			continue;
+
+		const auto& params = ci.func->GetType()->Params();
+		auto args = MakeCallArgumentVector(ci.args, params);
+
+		auto elem = make_backtrace_element(ci.func->Name(), std::move(args),
+		                                   ci.call ? ci.call->GetLocationInfo() : nullptr);
+		rval->Append(std::move(elem));
+		}
+
+	return rval;
+	}
+
 static void emit_builtin_error_common(const char* msg, Obj* arg, bool unwind)
 	{
 	auto emit = [=](const CallExpr* ce)
diff --git a/src/Func.h b/src/Func.h
index a27eb892b7..06f2d26306 100644
--- a/src/Func.h
+++ b/src/Func.h
@@ -364,6 +364,25 @@ private:
 
 extern std::vector<CallInfo> call_stack;
 
+/**
+ * Create a single BacktraceElement record val.
+ *
+ * @param name the name of the function.
+ * @param args call argument vector created by MakeCallArgumentVector().
+ * @param loc optional location information of the caller.
+ *
+ * @return record value representing a BacktraceElement.
+ */
+zeek::RecordValPtr make_backtrace_element(std::string_view name, const VectorValPtr args,
+                                          const zeek::detail::Location* loc);
+
+/**
+ * Create a Zeek script Backtrace of the current script call_stack.
+ *
+ * @return VectorValPtr containing BacktraceElement entries.
+ */
+zeek::VectorValPtr get_current_script_backtrace();
+
 // This is set to true after the built-in functions have been initialized.
 extern bool did_builtin_init;
 extern std::vector<void (*)()> bif_initializers;
diff --git a/src/Reporter.h b/src/Reporter.h
index c243d6e98d..8f8e54e251 100644
--- a/src/Reporter.h
+++ b/src/Reporter.h
@@ -31,6 +31,7 @@ using StringValPtr = IntrusivePtr<StringVal>;
 namespace detail
 	{
 
+class AssertStmt;
 class Location;
 class Expr;
 
@@ -59,6 +60,7 @@ class InterpreterException : public ReporterException
 	{
 protected:
 	friend class Reporter;
+	friend class detail::AssertStmt;
 	InterpreterException() { }
 	};
 
diff --git a/src/Stmt.cc b/src/Stmt.cc
index 1150740a9d..acdad6b8f8 100644
--- a/src/Stmt.cc
+++ b/src/Stmt.cc
@@ -54,6 +54,7 @@ const char* stmt_name(StmtTag t)
 		"ZAM",
 		"ZAM-resumption",
 		"null",
+		"assert",
 	};
 
 	return stmt_names[int(t)];
@@ -1864,6 +1865,140 @@ TraversalCode NullStmt::Traverse(TraversalCallback* cb) const
 	HANDLE_TC_STMT_POST(tc);
 	}
 
+AssertStmt::AssertStmt(ExprPtr arg_cond, ExprPtr arg_msg)
+	: Stmt(STMT_ASSERT), cond(std::move(arg_cond)), msg(std::move(arg_msg))
+	{
+	if ( ! IsBool(cond->GetType()->Tag()) )
+		cond->Error("conditional must be boolean");
+
+	if ( msg && ! IsString(msg->GetType()->Tag()) )
+		msg->Error("message must be string");
+	}
+
+ValPtr AssertStmt::Exec(Frame* f, StmtFlowType& flow)
+	{
+	RegisterAccess();
+	flow = FLOW_NEXT;
+
+	static auto assertion_failure_hook = id::find_func("assertion_failure");
+	static auto assertion_result_hook = id::find_func("assertion_result");
+
+	bool run_result_hook = assertion_result_hook && assertion_result_hook->HasEnabledBodies();
+	bool run_failure_hook = assertion_failure_hook && assertion_failure_hook->HasEnabledBodies();
+
+	auto assert_result = cond->Eval(f)->AsBool();
+
+	if ( assert_result && ! run_result_hook )
+		return Val::nil;
+
+	// Textual representation of cond from the AST.
+	static zeek::ODesc desc;
+	desc.Clear();
+	desc.SetShort(true);
+	desc.SetQuotes(true);
+	cond->Describe(&desc);
+	auto cond_val = zeek::make_intrusive<zeek::StringVal>(desc.Len(), (const char*)desc.Bytes());
+
+	zeek::StringValPtr msg_val = zeek::val_mgr->EmptyString();
+	if ( msg )
+		{
+		// Eval() may fail if expression assumes assert
+		// condition is F, but we still try to get it for
+		// the assertion_result hook.
+		try
+			{
+			msg_val = cast_intrusive<zeek::StringVal>(msg->Eval(f));
+			}
+		catch ( InterpreterException& e )
+			{
+			desc.Clear();
+			desc.Add("<error eval ");
+			msg->Describe(&desc);
+			desc.Add(">");
+			msg_val = zeek::make_intrusive<zeek::StringVal>(desc.Len(), (const char*)desc.Bytes());
+			}
+		}
+
+	VectorValPtr bt = nullptr;
+	if ( run_result_hook || run_failure_hook )
+		{
+		bt = get_current_script_backtrace();
+		auto assert_elem = make_backtrace_element("assert", MakeEmptyCallArgumentVector(),
+		                                          GetLocationInfo());
+		bt->Insert(0, assert_elem);
+		}
+
+	// Breaking from either the assertion_failure() or assertion_result()
+	// hook can be used to suppress the default log message.
+	bool report_error = true;
+
+	if ( run_result_hook )
+		report_error &= assertion_result_hook
+		                    ->Invoke(zeek::val_mgr->Bool(assert_result), cond_val, msg_val, bt)
+		                    ->AsBool();
+
+	if ( assert_result )
+		return Val::nil;
+
+	if ( run_failure_hook )
+		report_error &= assertion_failure_hook->Invoke(cond_val, msg_val, bt)->AsBool();
+
+	if ( report_error )
+		{
+		std::string reporter_msg = util::fmt("assertion failure: %s", cond_val->CheckString());
+		if ( msg_val->Len() > 0 )
+			reporter_msg += util::fmt(" (%s)", msg_val->CheckString());
+
+		reporter->PushLocation(GetLocationInfo());
+		reporter->Error("%s", reporter_msg.c_str());
+		reporter->PopLocation();
+		}
+
+	throw InterpreterException();
+	}
+
+void AssertStmt::StmtDescribe(ODesc* d) const
+	{
+	Stmt::StmtDescribe(d);
+
+	// Quoting strings looks better when describing assert
+	// statements. So turn it on explicitly.
+	//
+	// E.g., md5_hash("") ends up as md5_hash() without quoting.
+	auto orig_quotes = d->WantQuotes();
+	d->SetQuotes(true);
+
+	cond->Describe(d);
+
+	if ( msg )
+		{
+		d->Add(",");
+		d->SP();
+		msg->Describe(d);
+		}
+
+	DescribeDone(d);
+
+	d->SetQuotes(orig_quotes);
+	}
+
+TraversalCode AssertStmt::Traverse(TraversalCallback* cb) const
+	{
+	TraversalCode tc = cb->PreStmt(this);
+	HANDLE_TC_STMT_PRE(tc);
+
+	tc = cond->Traverse(cb);
+	HANDLE_TC_STMT_PRE(tc);
+	if ( msg )
+		{
+		tc = msg->Traverse(cb);
+		HANDLE_TC_STMT_PRE(tc);
+		}
+
+	tc = cb->PostStmt(this);
+	HANDLE_TC_STMT_POST(tc);
+	}
+
 WhenInfo::WhenInfo(ExprPtr arg_cond, FuncType::CaptureList* arg_cl, bool arg_is_return)
 	: cond(std::move(arg_cond)), cl(arg_cl), is_return(arg_is_return)
 	{
diff --git a/src/Stmt.h b/src/Stmt.h
index 5625b54502..bd91bdd7e4 100644
--- a/src/Stmt.h
+++ b/src/Stmt.h
@@ -544,6 +544,25 @@ private:
 	bool is_directive;
 	};
 
+class AssertStmt final : public Stmt
+	{
+public:
+	explicit AssertStmt(ExprPtr cond, ExprPtr msg = nullptr);
+
+	ValPtr Exec(Frame* f, StmtFlowType& flow) override;
+
+	void StmtDescribe(ODesc* d) const override;
+
+	TraversalCode Traverse(TraversalCallback* cb) const override;
+
+	// Optimization-related:
+	StmtPtr Duplicate() override;
+
+private:
+	ExprPtr cond;
+	ExprPtr msg;
+	};
+
 // A helper class for tracking all of the information associated with
 // a "when" statement, and constructing the necessary components in support
 // of lambda-style captures.
diff --git a/src/StmtBase.h b/src/StmtBase.h
index dc7bb375c3..17188e0ce1 100644
--- a/src/StmtBase.h
+++ b/src/StmtBase.h
@@ -29,6 +29,7 @@ namespace detail
 class CompositeHash;
 class Frame;
 
+class AssertStmt;
 class CatchReturnStmt;
 class ExprStmt;
 class ForStmt;
@@ -94,6 +95,7 @@ public:
 	const WhenStmt* AsWhenStmt() const;
 	const SwitchStmt* AsSwitchStmt() const;
 	const NullStmt* AsNullStmt() const;
+	const AssertStmt* AsAssertStmt() const;
 
 	void RegisterAccess() const
 		{
diff --git a/src/StmtEnums.h b/src/StmtEnums.h
index 1252edb43d..75f500f91c 100644
--- a/src/StmtEnums.h
+++ b/src/StmtEnums.h
@@ -32,8 +32,9 @@ enum StmtTag
 	STMT_CPP, // compiled C++
 	STMT_ZAM, // a ZAM function body
 	STMT_ZAM_RESUMPTION, // resumes ZAM execution for "when" statements
-	STMT_NULL
-#define NUM_STMTS (int(STMT_NULL) + 1)
+	STMT_NULL,
+	STMT_ASSERT,
+#define NUM_STMTS (int(STMT_ASSERT) + 1)
 	};
 
 enum StmtFlowType
diff --git a/src/ZeekArgs.cc b/src/ZeekArgs.cc
index 503cd98ff4..8db4264cf7 100644
--- a/src/ZeekArgs.cc
+++ b/src/ZeekArgs.cc
@@ -52,4 +52,10 @@ VectorValPtr MakeCallArgumentVector(const Args& vals, const RecordTypePtr& types
 	return rval;
 	}
 
+VectorValPtr MakeEmptyCallArgumentVector()
+	{
+	static auto call_argument_vector = id::find_type<VectorType>("call_argument_vector");
+	return make_intrusive<VectorVal>(call_argument_vector);
+	}
+
 	} // namespace zeek
diff --git a/src/ZeekArgs.h b/src/ZeekArgs.h
index 27acea28b1..6d4cf15d74 100644
--- a/src/ZeekArgs.h
+++ b/src/ZeekArgs.h
@@ -39,4 +39,11 @@ Args val_list_to_args(const ValPList& vl);
  */
 VectorValPtr MakeCallArgumentVector(const Args& vals, const RecordTypePtr& types);
 
+/**
+ * Creates an empty "call_argument_vector" vector.
+ *
+ * @return empty vector of script-level type "call_argument_vector"
+ */
+VectorValPtr MakeEmptyCallArgumentVector();
+
 	} // namespace zeek
diff --git a/src/parse.y b/src/parse.y
index 4db15571ab..d16fc5042c 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -7,7 +7,7 @@
 
 %expect 211
 
-%token TOK_ADD TOK_ADD_TO TOK_ADDR TOK_ANY
+%token TOK_ADD TOK_ADD_TO TOK_ADDR TOK_ANY TOK_ASSERT
 %token TOK_ATENDIF TOK_ATELSE TOK_ATIF TOK_ATIFDEF TOK_ATIFNDEF
 %token TOK_BOOL TOK_BREAK TOK_CASE TOK_OPTION TOK_CONST
 %token TOK_CONSTANT TOK_COPY TOK_COUNT TOK_DEFAULT TOK_DELETE
@@ -78,6 +78,7 @@
 %type <captures> capture_list opt_captures when_captures
 %type <when_clause> when_head when_start when_clause
 %type <re_modes> TOK_PATTERN_END
+%type <expr> opt_assert_msg
 
 %{
 #include <cstdlib>
@@ -1802,6 +1803,11 @@ stmt:
 			    script_coverage_mgr.DecIgnoreDepth();
 			}
 
+	|	TOK_ASSERT expr opt_assert_msg ';'
+			{
+			$$ = new AssertStmt(IntrusivePtr{AdoptRef{}, $2}, {AdoptRef{}, $3});
+			}
+
 	|	TOK_PRINT expr_list ';' opt_no_test
 			{
 			set_location(@1, @3);
@@ -2228,6 +2234,13 @@ resolve_id:
 			}
 	;
 
+opt_assert_msg:
+		',' expr
+			{ $$ = $2; }
+	|
+			{ $$ = nullptr; }
+	;
+
 opt_no_test:
 		TOK_NO_TEST
 			{ $$ = true; }
diff --git a/src/scan.l b/src/scan.l
index c961b928e2..f1a8ecd201 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -321,6 +321,7 @@ add	return TOK_ADD;
 addr	return TOK_ADDR;
 any	return TOK_ANY;
 as	return TOK_AS;
+assert	return TOK_ASSERT;
 bool	return TOK_BOOL;
 break	return TOK_BREAK;
 case	return TOK_CASE;
diff --git a/src/script_opt/Stmt.cc b/src/script_opt/Stmt.cc
index bb3e0c551b..02afbe7ae3 100644
--- a/src/script_opt/Stmt.cc
+++ b/src/script_opt/Stmt.cc
@@ -919,6 +919,11 @@ StmtPtr InitStmt::DoReduce(Reducer* c)
 	return ThisPtr();
 	}
 
+StmtPtr AssertStmt::Duplicate()
+	{
+	return SetSucc(new AssertStmt(cond->Duplicate(), msg ? msg->Duplicate() : nullptr));
+	}
+
 StmtPtr WhenStmt::Duplicate()
 	{
 	FuncType::CaptureList* cl_dup = nullptr;
diff --git a/src/zeek.bif b/src/zeek.bif
index c97e6e7d9c..1ad2324e04 100644
--- a/src/zeek.bif
+++ b/src/zeek.bif
@@ -2368,6 +2368,10 @@ function is_v6_subnet%(s: subnet%): bool
 		return zeek::val_mgr->False();
 	%}
 
+%%{
+#include "zeek/Func.h"
+%%}
+
 ## Returns a representation of the call stack as a vector of call stack
 ## elements, each containing call location information.
 ##
@@ -2375,49 +2379,7 @@ function is_v6_subnet%(s: subnet%): bool
 ##          location information.
 function backtrace%(%): Backtrace
 	%{
-	using zeek::detail::call_stack;
-	static auto backtrace_type = id::find_type<VectorType>("Backtrace");
-	static auto elem_type = id::find_type<RecordType>("BacktraceElement");
-	static auto function_name_idx = elem_type->FieldOffset("function_name");
-	static auto function_args_idx = elem_type->FieldOffset("function_args");
-	static auto file_location_idx = elem_type->FieldOffset("file_location");
-	static auto line_location_idx = elem_type->FieldOffset("line_location");
-
-	auto rval = make_intrusive<VectorVal>(backtrace_type);
-
-	// The body of the following loop can wind up adding items to
-	// the call stack (because MakeCallArgumentVector() evaluates
-	// default arguments, which can in turn involve calls to script
-	// functions), so we work from a copy of the current call stack
-	// to prevent problems with iterator invalidation.
-	auto cs_copy = call_stack;
-
-	for ( auto it = cs_copy.rbegin(); it != cs_copy.rend(); ++it )
-		{
-		const auto& ci = *it;
-		if ( ! ci.func )
-			// This happens for compiled code.
-			continue;
-
-		auto elem = make_intrusive<RecordVal>(elem_type);
-
-		const auto& params = ci.func->GetType()->Params();
-		auto args = MakeCallArgumentVector(ci.args, params);
-
-		elem->Assign(function_name_idx, ci.func->Name());
-		elem->Assign(function_args_idx, std::move(args));
-
-		if ( ci.call )
-			{
-			auto loc = ci.call->GetLocationInfo();
-			elem->Assign(file_location_idx, loc->filename);
-			elem->Assign(line_location_idx, loc->first_line);
-			}
-
-		rval->Assign(rval->Size(), std::move(elem));
-		}
-
-	return rval;
+	return zeek::detail::get_current_script_backtrace();
 	%}
 
 # ===========================================================================
diff --git a/testing/btest/Baseline/language.assert-2/out b/testing/btest/Baseline/language.assert-2/out
new file mode 100644
index 0000000000..40ed4ca014
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-2/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 3: assertion failure: fmt("%s", 1) == "2" ("1" != "2")
+fatal error: errors occurred while initializing
diff --git a/testing/btest/Baseline/language.assert-3/out b/testing/btest/Baseline/language.assert-3/out
new file mode 100644
index 0000000000..5a58147fa5
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-3/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 3: assertion failure: (coerce to_count("42") to double) == 42.5 (always failing)
+fatal error: errors occurred while initializing
diff --git a/testing/btest/Baseline/language.assert-4/out b/testing/btest/Baseline/language.assert-4/out
new file mode 100644
index 0000000000..3146002d53
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-4/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 4: assertion failure: 1 == x (Expected x to be 1, have 2)
+fatal error: errors occurred while initializing
diff --git a/testing/btest/Baseline/language.assert-5/out b/testing/btest/Baseline/language.assert-5/out
new file mode 100644
index 0000000000..166362e0c3
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-5/out
@@ -0,0 +1,6 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 9: assertion failure: "ghi" in tbl ({
+	[abc] = 123,
+	[def] = 456
+})
+fatal error: errors occurred while initializing
diff --git a/testing/btest/Baseline/language.assert-6/out b/testing/btest/Baseline/language.assert-6/out
new file mode 100644
index 0000000000..4bcf7b428e
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-6/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 10: assertion failure: r?$b (r$b is not set in [a=1234, b=<uninitialized>])
+fatal error: errors occurred while initializing
diff --git a/testing/btest/Baseline/language.assert-7/out b/testing/btest/Baseline/language.assert-7/out
new file mode 100644
index 0000000000..c28e697ecb
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-7/out
@@ -0,0 +1,4 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+expression error in <...>/assert.zeek, line 10: field value missing (r$b)
+error in <...>/assert.zeek, line 10: assertion failure: r?$b (<error eval fmt("r$b is not set trying anyway: %s", r$b)>)
+fatal error: errors occurred while initializing
diff --git a/testing/btest/Baseline/language.assert-8/out b/testing/btest/Baseline/language.assert-8/out
new file mode 100644
index 0000000000..7d877b65b5
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-8/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 2: assertion failure: 1 == 2 (always false)
+fatal error: failed to execute script statements at top-level scope
diff --git a/testing/btest/Baseline/language.assert-error-2/.stderr b/testing/btest/Baseline/language.assert-error-2/.stderr
new file mode 100644
index 0000000000..ffba84808c
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-error-2/.stderr
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-error.zeek, line 3: message must be string (1234)
diff --git a/testing/btest/Baseline/language.assert-error-3/.stderr b/testing/btest/Baseline/language.assert-error-3/.stderr
new file mode 100644
index 0000000000..8bbc43e570
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-error-3/.stderr
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-error.zeek, line 3: syntax error, at or near ";"
diff --git a/testing/btest/Baseline/language.assert-error-4/.stderr b/testing/btest/Baseline/language.assert-error-4/.stderr
new file mode 100644
index 0000000000..90ff2d507a
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-error-4/.stderr
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-error.zeek, line 3: syntax error, at or near ","
diff --git a/testing/btest/Baseline/language.assert-error/.stderr b/testing/btest/Baseline/language.assert-error/.stderr
new file mode 100644
index 0000000000..1f636a5228
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-error/.stderr
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-error.zeek, line 8: conditional must be boolean (1)
diff --git a/testing/btest/Baseline/language.assert-hook-2/.stderr b/testing/btest/Baseline/language.assert-hook-2/.stderr
new file mode 100644
index 0000000000..49d861c74c
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-2/.stderr
@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
diff --git a/testing/btest/Baseline/language.assert-hook-2/out b/testing/btest/Baseline/language.assert-hook-2/out
new file mode 100644
index 0000000000..f898a52732
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-2/out
@@ -0,0 +1,7 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_failure, to_count("5") == 4, 5 is not 4
+assert <...>/assert-hook.zeek:21
+ f <...>/assert-hook.zeek:25
+  g <...>/assert-hook.zeek:26
+   h <...>/assert-hook.zeek:30
+    zeek_init <none>:0
diff --git a/testing/btest/Baseline/language.assert-hook-3/.stderr b/testing/btest/Baseline/language.assert-hook-3/.stderr
new file mode 100644
index 0000000000..a1707e3408
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-3/.stderr
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-hook.zeek, line 12: assertion failure: F (terminate me!)
+received termination signal
diff --git a/testing/btest/Baseline/language.assert-hook-3/out b/testing/btest/Baseline/language.assert-hook-3/out
new file mode 100644
index 0000000000..a09aae6630
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-3/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_failure, terminate me!
+zeek_done()
diff --git a/testing/btest/Baseline/language.assert-hook-4/.stderr b/testing/btest/Baseline/language.assert-hook-4/.stderr
new file mode 100644
index 0000000000..49d861c74c
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-4/.stderr
@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
diff --git a/testing/btest/Baseline/language.assert-hook-4/out b/testing/btest/Baseline/language.assert-hook-4/out
new file mode 100644
index 0000000000..13dabea91e
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-4/out
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_failure, calling exit!
diff --git a/testing/btest/Baseline/language.assert-hook-5/.stderr b/testing/btest/Baseline/language.assert-hook-5/.stderr
new file mode 100644
index 0000000000..49d861c74c
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-5/.stderr
@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
diff --git a/testing/btest/Baseline/language.assert-hook-5/out b/testing/btest/Baseline/language.assert-hook-5/out
new file mode 100644
index 0000000000..cfd12f766e
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-5/out
@@ -0,0 +1,8 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_result T at <...>/assert-hook.zeek:25: md5_hash("") == "d41d8cd98f00b204e9800998ecf8427e"
+assertion_result T at <...>/assert-hook.zeek:30: sha1_hash("") == "da39a3ee5e6b4b0d3255bfef95601890afd80709"
+assertion_result F at <...>/assert-hook.zeek:35: sha1_hash("") == "wrong"
+assertion_failure at <...>/assert-hook.zeek:35: sha1_hash("") == "wrong"
+assertion_result F at <...>/assert-hook.zeek:40: md5_hash("") == "wrong"
+assertion_failure at <...>/assert-hook.zeek:40: md5_hash("") == "wrong"
+2 of 4 assertions failed
diff --git a/testing/btest/Baseline/language.assert-hook-6/.stderr b/testing/btest/Baseline/language.assert-hook-6/.stderr
new file mode 100644
index 0000000000..13dbb41dae
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-6/.stderr
@@ -0,0 +1,5 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+expression error in <...>/assert-hook.zeek, line 15: field value missing (get_current_packet_header()$ip)
+expression error in <...>/assert-hook.zeek, line 17: field value missing (get_current_packet_header()$ip)
+error in <...>/assert-hook.zeek, line 17: assertion failure: 2 + 2 == 5 (<error eval cat(get_current_packet_header()$ip)>)
+error in <...>/assert-hook.zeek, line 22: assertion failure: 2 + 2 == 5 ({"msg":"false and works"})
diff --git a/testing/btest/Baseline/language.assert-hook-6/out b/testing/btest/Baseline/language.assert-hook-6/out
new file mode 100644
index 0000000000..37d07df4b9
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-6/out
@@ -0,0 +1,7 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_result, T, 2 + 2 == 4, <error eval cat(get_current_packet_header()$ip)>, <...>/assert-hook.zeek, 15
+assertion_result, T, 2 + 2 == 4, {"msg":"true and works"}, <...>/assert-hook.zeek, 16
+assertion_result, F, 2 + 2 == 5, <error eval cat(get_current_packet_header()$ip)>, <...>/assert-hook.zeek, 17
+assertion_failure, 2 + 2 == 5, <error eval cat(get_current_packet_header()$ip)>, <...>/assert-hook.zeek, 17
+assertion_result, F, 2 + 2 == 5, {"msg":"false and works"}, <...>/assert-hook.zeek, 22
+assertion_failure, 2 + 2 == 5, {"msg":"false and works"}, <...>/assert-hook.zeek, 22
diff --git a/testing/btest/Baseline/language.assert-hook-7/.stderr b/testing/btest/Baseline/language.assert-hook-7/.stderr
new file mode 100644
index 0000000000..49d861c74c
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-7/.stderr
@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
diff --git a/testing/btest/Baseline/language.assert-hook-7/out b/testing/btest/Baseline/language.assert-hook-7/out
new file mode 100644
index 0000000000..820b6a66a1
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook-7/out
@@ -0,0 +1,5 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_result, T, 2 + 2 == 4, this is true, <...>/assert-hook.zeek, 10
+assertion_result, T, 2 + 2 == 4, {"msg":"this is also true"}, <...>/assert-hook.zeek, 11
+assertion_result, F, 2 + 2 == 5, this is false, <...>/assert-hook.zeek, 12
+assertion_result, F, 2 + 2 == 5, this is false, <...>/assert-hook.zeek, 18
diff --git a/testing/btest/Baseline/language.assert-hook/.stderr b/testing/btest/Baseline/language.assert-hook/.stderr
new file mode 100644
index 0000000000..70a0f9c3a1
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook/.stderr
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-hook.zeek, line 15: assertion failure: 1 != 1
diff --git a/testing/btest/Baseline/language.assert-hook/out b/testing/btest/Baseline/language.assert-hook/out
new file mode 100644
index 0000000000..f92c1a466f
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-hook/out
@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+assertion_failure, 1 != 1, , <...>/assert-hook.zeek, 15
diff --git a/testing/btest/Baseline/language.assert-misc/out b/testing/btest/Baseline/language.assert-misc/out
new file mode 100644
index 0000000000..1298f95384
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-misc/out
@@ -0,0 +1,13 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+f, lambda_<505728364269398358>
+{ 
+assert 0 < getpid(), fmt("my pid is funny: %s", getpid());
+}
+g, lambda_<8496146571423528161>
+{ 
+assert to_count("42") == 42;
+}
+test_function, test_function
+{ 
+assert 0 < getpid();
+}
diff --git a/testing/btest/Baseline/language.assert-top-level/.stderr b/testing/btest/Baseline/language.assert-top-level/.stderr
new file mode 100644
index 0000000000..18c84b3171
--- /dev/null
+++ b/testing/btest/Baseline/language.assert-top-level/.stderr
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert-top-level.zeek, line 5: assertion failure: getpid() == 0 (my pid greater 0? T)
+fatal error: failed to execute script statements at top-level scope
diff --git a/testing/btest/Baseline/language.assert/out b/testing/btest/Baseline/language.assert/out
new file mode 100644
index 0000000000..256b93f1c8
--- /dev/null
+++ b/testing/btest/Baseline/language.assert/out
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/assert.zeek, line 8: assertion failure: fmt("%s", 1) == "2"
+fatal error: errors occurred while initializing
diff --git a/testing/btest/language/assert-error.zeek b/testing/btest/language/assert-error.zeek
new file mode 100644
index 0000000000..3ae8384e3d
--- /dev/null
+++ b/testing/btest/language/assert-error.zeek
@@ -0,0 +1,27 @@
+# @TEST-DOC: Assert statement wrong usage
+#
+# @TEST-EXEC-FAIL: zeek -b %INPUT
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff .stderr
+
+event zeek_init()
+	{
+	assert 1;
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	assert T, 1234;
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	assert;
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	assert T, "extra", "something";
+	}
diff --git a/testing/btest/language/assert-hook.zeek b/testing/btest/language/assert-hook.zeek
new file mode 100644
index 0000000000..1edca8ee6b
--- /dev/null
+++ b/testing/btest/language/assert-hook.zeek
@@ -0,0 +1,195 @@
+# @TEST-DOC: Assert statement testing with assertion_failure and assertion_result implementation.
+#
+# @TEST-EXEC: zeek -b %INPUT >out
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff out
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff .stderr
+
+# Hook is not calling break: Reporter log is produced.
+hook assertion_failure(cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_failure", cond, msg, bt[0]$file_location, bt[0]$line_location;
+	}
+
+event zeek_init()
+	{
+	assert 1 != 1;
+	print "not reached";
+	}
+
+@TEST-START-NEXT
+# Test the backtrace location, also calling break to suppress reporter log.
+hook assertion_failure(cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_failure", cond, msg;
+	local indent = "";
+	for ( _, e in bt )
+		{
+		local file_name = e?$file_location ? e$file_location : "<none>";
+		local line_number = e?$line_location ? e$line_location : 0;
+		print fmt("%s%s %s:%s", indent, e$function_name, file_name, line_number);
+		indent = fmt("%s ", indent);
+		}
+
+	break;
+	}
+
+
+function f()
+	{
+	assert md5_hash("") == "d41d8cd98f00b204e9800998ecf8427e";
+	assert to_count("5") == 4, fmt("5 is not 4");
+	assert sha1_hash("") == "da39a3ee5e6b4b0d3255bfef95601890afd80709";
+	}
+
+function g() { f(); }
+function h() { g(); }
+
+event zeek_init()
+	{
+	h();
+	print "not reached";
+	}
+
+@TEST-START-NEXT
+# Calling terminate() from the assertion hook.
+redef exit_only_after_terminate = T;
+
+hook assertion_failure(cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_failure", msg;
+	terminate();
+	}
+
+event zeek_init()
+	{
+	assert F, "terminate me!";
+	print "not reached";
+	}
+
+event zeek_done()
+	{
+	print "zeek_done()";
+	assert zeek_is_terminating(), "zeek_done() should have zeek terminating";
+	}
+
+@TEST-START-NEXT
+# Calling exit() from the assertion hook.
+redef exit_only_after_terminate = T;
+
+hook assertion_failure(cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_failure", msg;
+	exit(0);  # in real tests use exit(1), this is to please btest.
+	}
+
+event zeek_init()
+	{
+	assert F, "calling exit!";
+	print "not reached";
+	}
+
+event zeek_done()
+	{
+	assert F, "zeek_done() not executed with exit()";
+	}
+
+@TEST-START-NEXT
+global assertion_failures = 0;
+global assertions_total = 0;
+
+hook assertion_failure(cond: string, msg: string, bt: Backtrace)
+	{
+	print fmt("assertion_failure at %s:%s: %s%s%s",
+	          bt[0]$file_location, bt[0]$line_location,
+	          cond, |msg| > 0 ? " - " : "", msg);
+
+	++assertion_failures;
+	break;
+	}
+
+hook assertion_result(result: bool, cond: string, msg: string, bt: Backtrace)
+	{
+	print fmt("assertion_result %s at %s:%s: %s%s%s",
+	          result, bt[0]$file_location, bt[0]$line_location,
+	          cond, |msg| > 0 ? " - " : "", msg);
+
+	++assertions_total;
+	}
+
+event zeek_test()
+	{
+	assert md5_hash("") == "d41d8cd98f00b204e9800998ecf8427e";
+	}
+
+event zeek_test()
+	{
+	assert sha1_hash("") == "da39a3ee5e6b4b0d3255bfef95601890afd80709";
+	}
+
+event zeek_test()
+	{
+	assert sha1_hash("") == "wrong";
+	}
+
+event zeek_test()
+	{
+	assert md5_hash("") == "wrong";
+	}
+
+event zeek_init()
+	{
+	event zeek_test();
+	}
+
+event zeek_done()
+	{
+	print fmt("%d of %d assertions failed", assertion_failures, assertions_total);
+	}
+
+@TEST-START-NEXT
+# Evaluating the msg expression can cause errors, see if we deal
+# with that gracefully.
+hook assertion_failure(cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_failure", cond, msg, bt[0]$file_location, bt[0]$line_location;
+	}
+
+hook assertion_result(result: bool, cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_result", result, cond, msg, bt[0]$file_location, bt[0]$line_location;
+	}
+
+event zeek_init()
+	{
+	assert 2 + 2 == 4, cat(get_current_packet_header()$ip);
+	assert 2 + 2 == 4, to_json([$msg="true and works"]);
+	assert 2 + 2 == 5, cat(get_current_packet_header()$ip);
+	}
+
+event zeek_done()
+	{
+	assert 2 + 2 == 5, to_json([$msg="false and works"]);
+	assert 2 + 2 == 5, cat(get_current_packet_header()$ip);
+	}
+
+@TEST-START-NEXT
+# Breaking in assertion_result() also suppresses the reporter errors.
+hook assertion_result(result: bool, cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_result", result, cond, msg, bt[0]$file_location, bt[0]$line_location;
+	break;
+	}
+
+event zeek_init()
+	{
+	assert 2 + 2 == 4, "this is true";
+	assert 2 + 2 == 4, to_json([$msg="this is also true"]);
+	assert 2 + 2 == 5, "this is false";
+	print "not reached";
+	}
+
+event zeek_done()
+	{
+	assert 2 + 2 == 5, "this is false";
+	print "not reached";
+	}
diff --git a/testing/btest/language/assert-misc.zeek b/testing/btest/language/assert-misc.zeek
new file mode 100644
index 0000000000..996ae3efd4
--- /dev/null
+++ b/testing/btest/language/assert-misc.zeek
@@ -0,0 +1,28 @@
+# @TEST-DOC: Test Describe() of assert statement. Expressions may be canonicalized.
+#
+# @TEST-EXEC: zeek -b %INPUT >out 2>&1
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff out
+
+function test_function()
+	{
+	assert getpid() > 0;
+	}
+
+event zeek_init()
+	{
+	local f = function() {
+		assert getpid() > 0, fmt("my pid is funny: %s", getpid());
+	};
+	local g = function() {
+		assert to_count("42") == 42;
+	};
+
+	print "f", f;
+	f();
+
+	print "g", g;
+	g();
+
+	print "test_function", test_function;
+	test_function();
+	}
diff --git a/testing/btest/language/assert-top-level.zeek b/testing/btest/language/assert-top-level.zeek
new file mode 100644
index 0000000000..738beca071
--- /dev/null
+++ b/testing/btest/language/assert-top-level.zeek
@@ -0,0 +1,5 @@
+# @TEST-EXEC-FAIL: zeek -b %INPUT >out
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff .stderr
+
+assert getpid() > 0;
+assert getpid() == 0, fmt("my pid greater 0? %s", getpid() > 0);
diff --git a/testing/btest/language/assert.zeek b/testing/btest/language/assert.zeek
new file mode 100644
index 0000000000..9fdffeaeae
--- /dev/null
+++ b/testing/btest/language/assert.zeek
@@ -0,0 +1,75 @@
+# @TEST-DOC: Assert statement behavior testing without an assertion_failure() hook.
+#
+# @TEST-EXEC-FAIL: unset ZEEK_ALLOW_INIT_ERRORS; zeek -b %INPUT >out 2>&1
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff out
+
+event zeek_init()
+	{
+	assert fmt("%s", 1) == "2";
+	print "not reached";
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	assert fmt("%s", 1) == "2", fmt("\"%s\" != \"2\"", 1);
+	print "not reached";
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	assert to_count("42") == 42.5, "always failing";
+	print "not reached";
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	local x = 2;
+	assert x == 1, fmt("Expected x to be 1, have %s", x);
+	print "not reached";
+	}
+
+@TEST-START-NEXT
+event zeek_init()
+	{
+	local tbl: table[string] of string = [
+		["abc"] = "123",
+		["def"] = "456",
+	];
+	assert "abc" in tbl, cat(tbl);
+	assert "def" in tbl, cat(tbl);
+	assert "ghi" in tbl, cat(tbl);
+	}
+
+@TEST-START-NEXT
+type MyRecord: record {
+	a: count;
+	b: count &optional;
+};
+
+event zeek_init()
+	{
+	local r: MyRecord = [$a=1234];
+	assert ! r?$b, fmt("Unexpected r$b is set to %s", r$b);
+	assert r?$b, fmt("r$b is not set in %s", r);
+	}
+
+@TEST-START-NEXT
+type MyRecord: record {
+	a: count;
+	b: count &optional;
+};
+
+event zeek_init()
+	{
+	local r: MyRecord = [$a=1234];
+	assert ! r?$b, fmt("Unexpected r$b is set to %s", r$b);
+	assert r?$b, fmt("r$b is not set trying anyway: %s", r$b);
+	}
+
+@TEST-START-NEXT
+assert 1 == 1, "always true";
+assert 1 == 2, "always false";
+print "not reached";