Fix jsonSet method to correct buffer extraction and add tests for string and stream conversions

Author: grongierisc

src/iop/cls/IOP/Message.cls

@@ -95,7 +95,7 @@ Method jsonSet(pInput) As %Status
 			// write in a stream
 			Set stream = ##class(%Stream.GlobalCharacter).%New()
 			for i=1:..#BUFFER:$LENGTH(pInput) {
-				Set sc = stream.Write($EXTRACT(pInput,i,(i+..#BUFFER)))
+				Set sc = stream.Write($EXTRACT(pInput,i,(i+..#BUFFER-1)))
 				Quit:$$$ISERR(sc)
 			}
 			Set r%jsonStream=stream, i%type="Stream"

src/tests/test_iop_utils.py

@@ -282,4 +282,60 @@ def test_migrate_only_classes():
         # Act
         _Utils.migrate()
         # Assert
-        assert True # if no exception is raised, the test is ok
+        assert True # if no exception is raised, the test is ok
+
+def test_string_to_stream():
+    string = 'test'
+    result = _Utils.string_to_stream(string)
+    expect = 'test'
+
+    assert result.Read() == expect
+
+def test_stream_to_string():
+    stream = iris.cls('%Stream.GlobalCharacter')._New()
+    stream.Write('test')
+    result = _Utils.stream_to_string(stream)
+    expect = 'test'
+
+    assert result == expect
+
+def test_stream_to_string_empty():
+    stream = iris.cls('%Stream.GlobalCharacter')._New()
+    result = _Utils.stream_to_string(stream)
+    expect = ''
+
+    assert result == expect
+
+def test_stream_to_string_huge():
+    stream = iris.cls('%Stream.GlobalCharacter')._New()
+    for i in range(1000):
+        stream.Write('test'*1000)
+    result = _Utils.stream_to_string(stream)
+    expect = 'test'*1000000
+
+    assert result == expect
+
+class TestIOPMessage:
+
+    def test_set_json_string(self):
+        msg = iris.cls('IOP.Message')._New()
+        msg.json = '{"test": "test"}'
+
+        assert msg.json == '{"test": "test"}'
+        assert msg.type == 'String'
+
+    def test_set_json_huge_string(self):
+        msg = iris.cls('IOP.Message')._New()
+        msg.json = '{"test": "test"}'*100000
+
+        assert _Utils.stream_to_string(msg.json) == '{"test": "test"}'*100000
+        assert msg.type == 'Stream'
+
+    def test_set_json_stream(self):
+        msg = iris.cls('IOP.Message')._New()
+        stream = iris.cls('%Stream.GlobalCharacter')._New()
+        stream.Write('{"test": "test"}')
+        msg.json = stream
+
+        assert msg.json.Read() == '{"test": "test"}'
+        assert msg.type == 'Stream'