diff --git a/tests/metabolomics/test_utils.py b/tests/metabolomics/test_utils.py
new file mode 100644
index 00000000..81dffa9b
--- /dev/null
+++ b/tests/metabolomics/test_utils.py
@@ -0,0 +1,100 @@
+import pytest
+from nplinker.metabolomics import MolecularFamily
+from nplinker.metabolomics import Spectrum
+from nplinker.metabolomics import add_annotation_to_spectrum
+from nplinker.metabolomics import add_spectrum_to_mf
+from nplinker.metabolomics import add_strains_to_spectrum
+from nplinker.metabolomics import get_spectra_from_mfs
+from nplinker.strain import Strain
+from nplinker.strain_collection import StrainCollection
+
+
+@pytest.fixture
+def spectra():
+    """Fixture for a list of Spectrum objects."""
+    # The order of the spectra is important for the tests.
+    return [
+        Spectrum("spec0", [100, 200], [0.1, 0.2], 150),
+        Spectrum("spec1", [100, 200], [0.1, 0.2], 150),
+        Spectrum("spec2", [100, 200], [0.1, 0.2], 150),
+    ]
+
+
+def test_add_annotation_to_spectrum(spectra):
+    """Test the add_annotation_to_spectrum function."""
+    annotations = {
+        "spec0": {"annotation": "annotation_0"},
+        "spec1": {"annotation": "annotation_1"},
+        "spec3": {"annotation": "annotation_3"},
+    }
+
+    add_annotation_to_spectrum(annotations, spectra)
+
+    for i, spec in enumerate(spectra):
+        if i < 2:
+            assert spec.gnps_annotations == {"annotation": f"annotation_{i}"}
+        else:
+            assert spec.gnps_annotations == {}
+
+
+def test_add_strains_to_spectrum(spectra):
+    """Test the add_strains_to_spectrum function."""
+    strains = StrainCollection()
+    strain0 = Strain("spec0")  # spectrum id as strain id
+    strain1 = Strain("strain1")
+    strain1.add_alias("spec1")  # spectrum id as strain alias
+    strains.add(strain0)
+    strains.add(strain1)
+
+    spectra_with_strains, spectra_without_strains = add_strains_to_spectrum(strains, spectra)
+
+    assert len(spectra_with_strains) == 2
+    assert len(spectra_without_strains) == 1
+    assert strain0 in spectra_with_strains[0].strains
+    assert strain1 in spectra_with_strains[1].strains
+    assert spectra_without_strains[0].strains == StrainCollection()
+
+
+def test_add_spectrum_to_mf(spectra):
+    """Test the add_spectrum_to_mf function."""
+    # Prepare the molecular families
+    mf0 = MolecularFamily("mf0")
+    mf0.spectra_ids = {"spec0", "spec1"}
+    mf1 = MolecularFamily("mf1")
+    mf1.spectra_ids = {
+        "spec2",
+        "spec-missing-1",
+    }
+    mf2 = MolecularFamily("mf2")
+    mf2.spectra_ids = {"spec-missing-2", "spec-missing-3"}
+    mfs = [mf0, mf1, mf2]
+
+    mf_with_spec, mf_without_spec, mf_missing_spec = add_spectrum_to_mf(spectra, mfs)
+
+    assert len(mf_with_spec) == 2
+    assert len(mf_without_spec) == 1
+    assert len(mf_missing_spec) == 2
+    assert mf_with_spec == [mf0, mf1]
+    assert mf_without_spec == [mf2]
+    assert mf_missing_spec == {mf1: {"spec-missing-1"}, mf2: {"spec-missing-2", "spec-missing-3"}}
+
+
+def test_get_spectra_from_mfs(spectra):
+    """Test the get_spectra_from_mfs function."""
+    mf0 = MolecularFamily("mf0")
+    mf0.spectra_ids = {"spec0", "spec1"}
+    mf0.add_spectrum(spectra[0])
+    mf0.add_spectrum(spectra[1])
+    mf1 = MolecularFamily("mf1")
+    mf1.spectra_ids = {
+        "spec2",
+        "spec-missing-1",
+    }
+    mf1.add_spectrum(spectra[2])
+    mf2 = MolecularFamily("mf2")
+    mf2.spectra_ids = {"spec-missing-2", "spec-missing-3"}
+    mfs = [mf0, mf1, mf2]
+
+    spec_from_mfs = get_spectra_from_mfs(mfs)
+
+    assert len(spec_from_mfs) == 3