Ensure peaks can be visualized properly

src/maldi_tools/plotting.py

@@ -163,13 +163,17 @@ def plot_peak_hist(peak: float, bin_count: int, extraction_dir: Path) -> None:
         extraction_dir (Path): The directory the peak images are saved in
     """
     # verify that the peak provided exists
-    peak_path = extraction_dir / f"{str(peak).replace('.', '_')}.tiff"
+    peak_file: str = f"{peak:.4f}".replace(".", "_")
+    peak_file = peak_file + ".tiff"
+    peak_path = Path(extraction_dir) / "float" / peak_file
     if not os.path.exists(peak_path):
-        raise FileNotFoundError(f"Peak {peak} does not have a corresponding peak image in {extraction_dir}")
+        raise FileNotFoundError(
+            f"Peak {peak:.4f} does not have a corresponding peak image in {extraction_dir}"
+        )
 
     # load the peak image in and display histogram
     peak_img: np.ndarray = io.imread(peak_path)
-    plt.hist(peak_img.values, bins=bin_count)
+    plt.hist(peak_img, bins=bin_count)
 
 
 def save_matched_peak_images(

tests/plotting_test.py

@@ -5,6 +5,7 @@
 
 import numpy as np
 import pandas as pd
+import pytest
 import xarray as xr
 from skimage.io import imread
 
@@ -82,6 +83,23 @@ def test_save_peak_images(image_xr: xr.DataArray, tmp_path: pathlib.Path):
         assert os.path.exists(iname)
 
 
+def test_plot_peak_hist(image_xr: xr.DataArray, tmp_path: pathlib.Path):
+    extraction_dir = tmp_path / "extraction_dir"
+    extraction_dir.mkdir(parents=True, exist_ok=True)
+
+    # ensure the test actually truncates to 4 digits correctly
+    image_xr = image_xr.assign_coords(peak=np.random.rand(6) * 100)
+
+    plotting.save_peak_images(image_xr=image_xr, extraction_dir=extraction_dir)
+
+    # this test should run to completion, since the peak can be loaded
+    plotting.plot_peak_hist(peak=image_xr.peak.values[0], bin_count=30, extraction_dir=extraction_dir)
+
+    # this test should fail since the peak does not exist
+    with pytest.raises(FileNotFoundError):
+        plotting.plot_peak_hist(peak=50.0123, bin_count=30, extraction_dir=extraction_dir)
+
+
 def test_save_matched_peak_images(rng: np.random.Generator, image_xr: xr.DataArray, tmp_path: pathlib.Path):
     extraction_dir = tmp_path / "extraction_dir"
     extraction_dir.mkdir(parents=True, exist_ok=True)