Don't crash when we have horizontal only (#170)

* Don't crash when we have horizontal only

* rm test for components

Author: matth-love

src/transformez/api.py

@@ -223,22 +223,24 @@ def build_components(
     vertical = None
     if source.vertical or target.vertical:
         if source.vertical is None or target.vertical is None:
-            raise ValueError("Both source and target vertical references are required.")
-
-        vertical = build_shift_grid(
-            region=region_obj,
-            increment=increment,
-            datum_in=src_srs,
-            datum_out=dst_srs,
-            cache_dir=cache_dir,
-            **vertical_options,
-        )
-
-        if source.horizontal is not None:
-            vertical = vertical.reproject(
-                source.horizontal,
-                dst_region=region_obj,
+            logger.debug(
+                f"Both source and target vertical references are required. {source.vertical} -> {target.vertical}"
             )
+        else:
+            vertical = build_shift_grid(
+                region=region_obj,
+                increment=increment,
+                datum_in=src_srs,
+                datum_out=dst_srs,
+                cache_dir=cache_dir,
+                **vertical_options,
+            )
+
+            if source.horizontal is not None:
+                vertical = vertical.reproject(
+                    source.horizontal,
+                    dst_region=region_obj,
+                )
 
     return TransformationComponents(
         horizontal=horizontal,

src/transformez/engines/htdp.py

@@ -30,7 +30,7 @@
 
 
 InstallScope = Literal["user", "project"]
-DEFAULT_HTDP_VERSION = "3.6.0"
+DEFAULT_HTDP_VERSION = "3.5.0"
 
 
 class HTDPInstallError(RuntimeError):

src/transformez/reference/bindings.py

@@ -327,7 +327,7 @@ class HtdpFrameBinding:
         reference_id="epsg:5869",
         engine="vdatum_grid",
         provider="vdatum",
-        provider_datum="mhhm",
+        provider_datum="mhhw",
         native_frame="EPSG:6319",
         default_model="g2018",
         global_proxy="global:hat",

tests/test_components.py

@@ -103,13 +103,16 @@ def test_build_components_vertical_is_aligned_to_source_crs(monkeypatch):
     assert kwargs["dst_region"] is region
 
 
-def test_build_components_requires_both_vertical_references():
-    with pytest.raises(
-        ValueError,
-        match="Both source and target vertical references are required",
-    ):
-        build_components(
-            "EPSG:4326+3855",
-            "EPSG:4326",
-            region=_region(),
-        )
+# Removing this test for now; i don't think we should crash here when
+# we're building components to allow just the horizontal component
+# to be built and returned...
+# def test_build_components_requires_both_vertical_references():
+#     with pytest.raises(
+#         ValueError,
+#         match="Both source and target vertical references are required",
+#     ):
+#         build_components(
+#             "EPSG:4326+3855",
+#             "EPSG:4326",
+#             region=_region(),
+#         )