Backport memory string test

examples/wasm-test/TestGeneral.gd

@@ -43,7 +43,7 @@ func test_load():
 
 func test_invalid_binary():
 	var wasm = Wasm.new()
-	var buffer = "asdf".to_utf8()
+	var buffer = Utils.to_utf8("asdf")
 	var error = wasm.compile(buffer)
 	expect_eq(error, ERR_INVALID_DATA)
 	expect_error("Invalid binary")

examples/wasm-test/TestMemory.gd

@@ -113,6 +113,19 @@ func test_memory_marshal():
 	var result = wasm.memory.seek(offset).get_var()
 	expect_eq(result, data)
 
+func test_string_sum():
+	var wasm = load_wasm("memory")
+	var offset = wasm.global("offset")
+	var string = "test_string" # String to store in Wasm memory
+	var sum = 0 # Sum of character UTF8 values
+	for c in Utils.to_utf8(string): sum += c
+	# Write string to memory using StreamPeer interface
+	# Note that Godot string marshalling prepends 32-bit string length
+	# See https://docs.godotengine.org/en/stable/classes/class_streampeer.html#class-streampeer-method-put-string
+	wasm.memory.seek(offset).put_string(string)
+	var result = wasm.function("ascii_sum", [])
+	expect_eq(result, sum)
+
 func test_resize():
 	var wasm = load_wasm("memory")
 	var memory = wasm.inspect().get("memory").get("current")

examples/wasm-test/utils/TestSuite.gd

@@ -39,7 +39,7 @@ func expect_error(s: String):
 	# Account for error stack trace
 	var regex = Utils.make_regex("^\\s+at:\\s")
 	var position = _log_file.get_position()
-	while _log_file.get_position() < _log_file.get_len():
+	while _log_file.get_position() < Utils.file_length(_log_file):
 		if !regex.search(_log_file.get_line()): break
 		position = _log_file.get_position()
 	_log_file.seek(position)

examples/wasm-test/utils/Utils.gd

@@ -8,3 +8,9 @@ static func make_regex(pattern: String) -> RegEx:
 	var regex = RegEx.new()
 	assert(regex.compile(pattern) == OK, "Invalid regex pattern: %s" % pattern)
 	return regex
+
+static func file_length(f: File) -> int:
+	return f.get_len()
+
+static func to_utf8(s: String) -> PoolByteArray:
+	return s.to_utf8()