Python: add minimal tests

Signed-off-by: Tristram Gräbener <tristram+git@tristramg.eu>

Author: Tristramg

python/.gitignore

@@ -0,0 +1 @@
+__pycache__

python/pyproject.toml

@@ -1,3 +1,9 @@
+[project]
+name = "liblrs_python"
+version = "0.2.6"
+requires-python = ">=3.12"
+dependencies = ["pip>=25.2"]
+
 [build-system]
 requires = ["maturin>=1.0,<2.0"]
 build-backend = "maturin"
@@ -10,6 +16,9 @@ features = ["pyo3/extension-module"]
 # That is why we add it explicitely when using sdist
 include = [{ path = "liblrs_python.pyi", format = "sdist" }]
 # Avoid a collision with the README.md at the root of the directory
-exclude = [{path = "README.md", format = "sdist"}]
+exclude = [{ path = "README.md", format = "sdist" }]
 # Reduce the binary size (from 8.9 to 1.4 when tested)
 strip = true
+
+[dependency-groups]
+dev = ["pytest"]

python/tests/test_build_and_load.py

@@ -0,0 +1,49 @@
+from pathlib import Path
+from liblrs_python import Builder, Point, Lrs, SegmentOfTraversal, AnchorOnLrm
+
+def build_lrm() -> Builder:
+    """Helper function that builds an example LRS with one lrm"""
+
+    # First we initialize the builder that will help us as we create new data
+    builder = Builder()
+
+    # We want to create a segment that has coordinates and nodes at its extremity
+    coords = [Point(0, 0), Point(0, 1)]
+    segment_id = "a small section of rail"
+    start_node = 0
+    end_node = 1
+    segment_handle = builder.add_segment(segment_id, coords, start_node, end_node)
+    
+    # Then we build a traversal with that segment
+    # Typically, a highway will be composed of many segments between each intersection
+    segment_reversed = False
+    segment_of_traversal = SegmentOfTraversal(segment_handle, segment_reversed)
+    traversal_id = "A very long railroad composed of many segments"
+    traversal_handle = builder.add_traversal(traversal_id, [segment_of_traversal])
+
+    # Anchors are reference points with coordinates that will help us to position ourself by measuring a distance from then
+    green_anchor = builder.add_anchor(id="Green House", coord=Point(0.01, 0), name="GH", properties={})
+    red_anchor = builder.add_anchor(id="Red House", coord=Point(-0.01, 1), name="RH", properties={})
+
+    # We associate those anchors to a traversal by defining a distance along that traversal
+    green_on_traversal = AnchorOnLrm(green_anchor, 0)
+    red_on_traversal = AnchorOnLrm(red_anchor, 1000)
+
+    # Now we have every thing to create a linear reference model
+    builder.add_lrm("My first Lrm", traversal_handle, [green_on_traversal, red_on_traversal], {})
+
+    return builder
+
+
+def test_build_in_memory():
+    builder = build_lrm()
+    lrs = builder.build_lrs({})
+    assert lrs.lrm_len() == 1
+
+def test_build_to_file(tmp_path: Path):
+    path = Path(tmp_path, "my_lrs")
+    builder = build_lrm()
+    builder.save(path, {})
+    with open(path, "rb") as lrs_file:
+        lrs = Lrs(lrs_file.read())
+        assert lrs.lrm_len() == 1