fix #34: strengthen tests with real content assertions; add proceedings mock

- test_input_formats: verify DOI appears in output, report.succeeded count
- test_integration: verify title/author fields in conference paper output
- test_python_api: fix empty-input test to expect ValidationError (code 1)
- mock_responses: add MOCK_CROSSREF_PROCEEDINGS_RESPONSE for proceedings-article path
- This also validates fix #28 works end-to-end (proceedings DOI resolves correctly)

Closes #34

Author: Ang

tests/mock_responses.py

@@ -55,6 +55,25 @@
 </feed>
 """
 
+# -- Crossref proceedings paper (10.5555/3295222.3295349, "Attention Is All You Need") --
+MOCK_CROSSREF_PROCEEDINGS_RESPONSE = {
+    "status": "ok",
+    "message-type": "work",
+    "message": {
+        "DOI": "10.5555/3295222.3295349",
+        "type": "proceedings-article",
+        "title": ["Attention Is All You Need"],
+        "author": [
+            {"given": "Ashish", "family": "Vaswani", "sequence": "first"},
+            {"given": "Noam", "family": "Shazeer", "sequence": "additional"},
+            {"given": "Niki", "family": "Parmar", "sequence": "additional"},
+        ],
+        "container-title": ["Advances in Neural Information Processing Systems"],
+        "published-print": {"date-parts": [[2017]]},
+        "publisher": "Curran Associates Inc.",
+    },
+}
+
 # -- Crossref title search (used by _resolve_doi_via_crossref_title) ----------
 MOCK_CROSSREF_SEARCH_RESPONSE = {
     "status": "ok",
@@ -164,6 +183,10 @@ def mock_requests_get(url, *args, **kwargs):
     if "api.crossref.org" in url and "10.1038/nature14539" in url:
         return MockResponse(json_data=MOCK_CROSSREF_RESPONSE)
 
+    # Crossref: proceedings DOI from Attention-Is-All-You-Need fuzzy search result
+    if "api.crossref.org" in url and "10.5555/3295222.3295349" in url:
+        return MockResponse(json_data=MOCK_CROSSREF_PROCEEDINGS_RESPONSE)
+
     # Crossref: title search (fuzzy-search path)
     if "api.crossref.org" in url and "query" in str(kwargs.get("params", "")):
         return MockResponse(json_data=MOCK_CROSSREF_SEARCH_RESPONSE)

tests/test_input_formats.py

@@ -8,9 +8,11 @@
 class TestInputFormats:
 
     def test_plain_doi(self, sample_references, run_onecite_process):
-        code, out, err, _ = run_onecite_process(sample_references["doi_only"], input_type="txt")
+        code, out, err, result = run_onecite_process(sample_references["doi_only"], input_type="txt")
         assert code == 0, err
         assert "@article" in out or "@inproceedings" in out
+        assert "10.1038/nature14539" in out, "DOI must appear in BibTeX output"
+        assert result["report"]["succeeded"] >= 1
 
     def test_multiline_txt(self, sample_references, run_onecite_process):
         """Two refs separated by a blank line."""
@@ -20,20 +22,24 @@ def test_multiline_txt(self, sample_references, run_onecite_process):
         assert out.count("@") >= 1
 
     def test_bibtex_input(self, sample_references, run_onecite_process):
-        code, _, err, _ = run_onecite_process(sample_references["bibtex_entry"], input_type="bib")
+        code, out, err, result = run_onecite_process(sample_references["bibtex_entry"], input_type="bib")
         assert code == 0, err
+        assert result["report"]["total"] >= 1
+        assert "@" in out, "BibTeX input should produce BibTeX output"
 
     def test_doi_variants(self, run_onecite_process):
-        """All common DOI notations should be recognised."""
+        """All common DOI notations must resolve to the same paper."""
         for doi in (
             "10.1038/nature14539",
             "doi:10.1038/nature14539",
             "DOI: 10.1038/nature14539",
             "https://doi.org/10.1038/nature14539",
         ):
-            code, out, err, _ = run_onecite_process(doi, input_type="txt")
+            code, out, err, result = run_onecite_process(doi, input_type="txt")
             assert code == 0, f"failed for {doi!r}: {err}"
             assert out.strip(), f"empty output for {doi!r}"
+            assert "10.1038/nature14539" in out, f"{doi!r} did not produce correct DOI in output"
+            assert result["report"]["succeeded"] == 1, f"{doi!r}: expected 1 succeeded"
 
     def test_arxiv_variants(self, run_onecite_process):
         for arxiv in ("1706.03762", "arxiv:1706.03762", "arXiv:1706.03762",

tests/test_integration.py

@@ -24,11 +24,13 @@ def test_readme_example(self, run_onecite_process):
         assert result["report"]["total"] >= 1
 
     def test_doi_to_bibtex(self, run_onecite_process):
-        code, _, err, result = run_onecite_process(
+        code, out, err, result = run_onecite_process(
             "10.1038/nature14539\n\n1706.03762", output_format="bibtex"
         )
         assert code == 0, err
         self._check(result)
+        assert "10.1038/nature14539" in out, "first DOI must appear in output"
+        assert result["report"]["succeeded"] >= 1
 
     def test_bib_to_bibtex(self, run_onecite_process):
         """Round-trip: feed an existing .bib entry, get enriched BibTeX back."""
@@ -48,12 +50,14 @@ def test_bib_to_bibtex(self, run_onecite_process):
         self._check(result)
 
     def test_conference_paper(self, run_onecite_process):
-        code, _, err, result = run_onecite_process(
+        code, out, err, result = run_onecite_process(
             "Attention is all you need\nVaswani et al.\nNIPS 2017",
             template="conference_paper",
         )
         assert code == 0, err
         self._check(result)
+        assert "Attention" in out or "attention" in out, "title must appear in output"
+        assert "Vaswani" in out or "vaswani" in out.lower(), "author must appear in output"
 
     def test_arxiv(self, run_onecite_process):
         code, _, err, result = run_onecite_process("1706.03762\n\narxiv:1512.03385")