refactor(tests): refactor test folder structure

This branch implements a restructuring of the test suite.

Rationale: Over-modularization of test parameter definitions clutters up the test
suite and leads to lengthy/repetitive import statements.

For now, the structure of the test suite should (loosely) mirror the
rdfproxy package structure, e.g. sparql_utils should be tested in
tests_sparql_utils etc.

Test types (unit, integration, end2end, etc) should be indicated in
docstrings or a separate tests README.

Closes #100

tests/data/models/dummy_model.py

@@ -0,0 +1,11 @@
+"""Simple dummy models e.g. for count query constructor testing."""
+
+from pydantic import BaseModel, ConfigDict
+
+
+class Dummy(BaseModel):
+    pass
+
+
+class GroupedDummy(BaseModel):
+    model_config = ConfigDict(group_by="x")

tests/data/parameters/count_query_parameters.py

@@ -0,0 +1,94 @@
+from tests.data.models.dummy_model import Dummy, GroupedDummy
+from tests.utils._types import CountQueryParameter
+
+
+construct_count_query_parameters = [
+    CountQueryParameter(
+        query="""
+        select ?x ?y ?z
+        where {
+            values (?x ?y ?z) {
+                (1 2 3)
+                (1 22 33)
+                (2 222 333)
+            }
+        }
+        """,
+        model=Dummy,
+        expected=3,
+    ),
+    CountQueryParameter(
+        query="""
+        select ?x ?y ?z
+        where {
+            values (?x ?y ?z) {
+                (1 2 3)
+                (1 22 33)
+                (2 222 333)
+            }
+        }
+        """,
+        model=GroupedDummy,
+        expected=2,
+    ),
+    CountQueryParameter(
+        query="""
+        select ?x ?y ?z
+        where {
+            values (?x ?y ?z) {
+                (1 2 3)
+                (1 22 33)
+                (1 22 33)
+                (2 222 333)
+            }
+        }
+        """,
+        model=Dummy,
+        expected=4,
+    ),
+    CountQueryParameter(
+        query="""
+        select ?x ?y ?z
+        where {
+            values (?x ?y ?z) {
+                (1 2 3)
+                (1 22 33)
+                (1 22 33)
+                (2 222 333)
+            }
+        }
+        """,
+        model=GroupedDummy,
+        expected=2,
+    ),
+    CountQueryParameter(
+        query="""
+        select ?x ?y ?z
+        where {
+            values (?x ?y ?z) {
+                (1 2 3)
+                (1 22 33)
+                (2 222 333)
+                (2 222 333)
+            }
+        }
+        """,
+        model=Dummy,
+        expected=4,
+    ),
+    CountQueryParameter(
+        query="""
+        select ?x ?y ?z
+        where {
+            values (?x ?y ?z) {
+                (1 2 3)
+                (1 22 33)
+                (2 222 333)
+                (2 222 333)
+            }
+        }
+        """,
+        model=GroupedDummy,
+        expected=2,
+    ),
+]