spdx3: write_snippet: fix the presentation of line and byte ranges

src/spdx_tools/spdx3/model/positive_integer_range.py

@@ -16,3 +16,6 @@ def __init__(
         end: int,
     ):
         check_types_and_set_values(self, locals())
+
+    def __str__(self):
+        return f"{self.begin}:{self.end}"

tests/spdx3/writer/tag_value/test_write_snippet.py

@@ -0,0 +1,25 @@
+import io
+
+from spdx_tools.spdx3.model.positive_integer_range import PositiveIntegerRange
+from spdx_tools.spdx3.model.software import Snippet
+from spdx_tools.spdx3.writer.console.software.snippet_writer import write_snippet
+
+
+def test_render_creation_info():
+    snippet = Snippet(
+        spdx_id="SPDXRef-Snippet",
+        byte_range=PositiveIntegerRange(0, 3),
+        line_range=PositiveIntegerRange(1, 2),
+    )
+    output_str = io.StringIO()
+    write_snippet(snippet, text_output=output_str)
+
+    assert (
+        output_str.getvalue()
+        == """\
+## Snippet
+SPDXID: SPDXRef-Snippet
+byte_range: 0:3
+line_range: 1:2
+"""
+    )