Use .zeek file suffix in unit tests

testing/btest/scripts/base/frameworks/input/optional.zeek

@@ -0,0 +1,53 @@
+# @TEST-EXEC: btest-bg-run bro bro -b %INPUT
+# @TEST-EXEC: btest-bg-wait 10
+# @TEST-EXEC: btest-diff out
+
+@TEST-START-FILE input.log
+#separator \x09
+#path	ssh
+#fields	i	b	
+#types	int	bool
+1	T
+2	T
+3	F
+4	F
+5	F
+6	F
+7	T
+@TEST-END-FILE
+
+redef exit_only_after_terminate = T;
+
+global outfile: file;
+
+redef InputAscii::empty_field = "EMPTY";
+
+module A;
+
+type Idx: record {
+	i: int;
+};
+
+type Val: record {
+	b: bool;
+	notb: bool &optional;
+};
+
+global servers: table[int] of Val = table();
+
+event bro_init()
+	{
+    outfile = open("../out");
+	# first read in the old stuff into the table...
+	Input::add_table([$source="../input.log", $name="input", $idx=Idx, $val=Val, $destination=servers, 
+				$pred(typ: Input::Event, left: Idx, right: Val) = { right$notb = !right$b; return T; }
+				]);
+	}
+
+event Input::end_of_data(name: string, source: string)
+	{
+	print outfile, servers;
+	Input::remove("input");
+	close(outfile);
+	terminate();
+	}