diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29..8b13789 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+
diff --git a/tests/fixtures/tabular/data.csv b/tests/fixtures/tabular/data.csv
new file mode 100644
index 0000000..aac51d8
--- /dev/null
+++ b/tests/fixtures/tabular/data.csv
@@ -0,0 +1,23 @@
+time;s0;s1;id
+0.0;0.0;10.0;m0
+1.0;1.0;9.0;m0
+2.0;2.0;8.0;m0
+3.0;3.0;7.0;m0
+4.0;4.0;6.0;m0
+5.0;5.0;5.0;m0
+6.0;6.0;4.0;m0
+7.0;7.0;3.0;m0
+8.0;8.0;2.0;m0
+9.0;9.0;1.0;m0
+10.0;10.0;0.0;m0
+0.0;0.0;10.0;m1
+1.0;1.0;9.0;m1
+2.0;2.0;8.0;m1
+3.0;3.0;7.0;m1
+4.0;4.0;6.0;m1
+5.0;5.0;5.0;m1
+6.0;6.0;4.0;m1
+7.0;7.0;3.0;m1
+8.0;8.0;2.0;m1
+9.0;9.0;1.0;m1
+10.0;10.0;0.0;m1
diff --git a/tests/fixtures/tabular/data.xlsx b/tests/fixtures/tabular/data.xlsx
new file mode 100644
index 0000000..bfec157
Binary files /dev/null and b/tests/fixtures/tabular/data.xlsx differ
diff --git a/tests/fixtures/tabular/data_invalid.csv b/tests/fixtures/tabular/data_invalid.csv
new file mode 100644
index 0000000..2199d4a
--- /dev/null
+++ b/tests/fixtures/tabular/data_invalid.csv
@@ -0,0 +1,23 @@
+s0;s1;id
+0.0;10.0;m0
+1.0;9.0;m0
+2.0;8.0;m0
+3.0;7.0;m0
+4.0;6.0;m0
+5.0;5.0;m0
+6.0;4.0;m0
+7.0;3.0;m0
+8.0;2.0;m0
+9.0;1.0;m0
+10.0;0.0;m0
+0.0;10.0;m1
+1.0;9.0;m1
+2.0;8.0;m1
+3.0;7.0;m1
+4.0;6.0;m1
+5.0;5.0;m1
+6.0;4.0;m1
+7.0;3.0;m1
+8.0;2.0;m1
+9.0;1.0;m1
+10.0;0.0;m1
diff --git a/tests/fixtures/tabular/data_invalid.xlsx b/tests/fixtures/tabular/data_invalid.xlsx
new file mode 100644
index 0000000..1fb2882
Binary files /dev/null and b/tests/fixtures/tabular/data_invalid.xlsx differ
diff --git a/tests/fixtures/tabular/data_invalid_chars.csv b/tests/fixtures/tabular/data_invalid_chars.csv
new file mode 100644
index 0000000..2e89614
--- /dev/null
+++ b/tests/fixtures/tabular/data_invalid_chars.csv
@@ -0,0 +1,23 @@
+s0;s1;id
+0.0;10.0;m0
+1.0;m1;m0
+2.0;8.0;m0
+3.0;7.0;m0
+m0;6.0;m0
+5.0;5.0;m0
+6.0;4.0;m0
+7.0;3.0;m0
+8.0;2.0;m0
+9.0;1.0;m0
+10.0;0.0;m0
+0.0;10.0;m1
+1.0;9.0;m1
+2.0;8.0;m1
+3.0;7.0;m1
+4.0;6.0;m1
+5.0;5.0;m1
+6.0;4.0;m1
+7.0;3.0;m1
+8.0;2.0;m1
+9.0;1.0;m1
+10.0;0.0;m1
diff --git a/tests/fixtures/tabular/measurement_export.csv b/tests/fixtures/tabular/measurement_export.csv
new file mode 100644
index 0000000..e69de29
diff --git a/tests/fixtures/tabular/measurement_invalid.json b/tests/fixtures/tabular/measurement_invalid.json
new file mode 100644
index 0000000..204c460
--- /dev/null
+++ b/tests/fixtures/tabular/measurement_invalid.json
@@ -0,0 +1,208 @@
+{
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+    "OBO": "http://purl.obolibrary.org/obo/",
+    "schema": "https://schema.org/",
+    "name": "schema:title",
+    "references": {
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+  "equations": [],
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+}
diff --git a/tests/fixtures/tabular/measurement_valid.json b/tests/fixtures/tabular/measurement_valid.json
new file mode 100644
index 0000000..ed462a2
--- /dev/null
+++ b/tests/fixtures/tabular/measurement_valid.json
@@ -0,0 +1,523 @@
+{
+  "@context": {
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+    "OBO": "http://purl.obolibrary.org/obo/",
+    "schema": "https://schema.org/",
+    "name": "schema:title",
+    "references": {
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+      "@type": "@id"
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+    "modified": "schema:dateModified",
+    "creators": "schema:creator"
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+  "@id": "enzml:EnzymeMLDocument/84fdaf73-0c33-4eb6-adc7-7f17b1523b4a",
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+  "vessels": [],
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+          "data_unit": {
+            "@context": {
+              "enzml": "http://www.enzymeml.org/v2/",
+              "OBO": "http://purl.obolibrary.org/obo/",
+              "schema": "https://schema.org/"
+            },
+            "@id": "OBO:UO_0000063",
+            "@type": [
+              "OBO:UO_0000000"
+            ],
+            "name": "mmol / l",
+            "base_units": [
+              {
+                "@context": {
+                  "enzml": "http://www.enzymeml.org/v2/",
+                  "OBO": "http://purl.obolibrary.org/obo/",
+                  "schema": "https://schema.org/"
+                },
+                "@id": "enzml:BaseUnit/b943545d-894b-445c-a745-c1215180ec8d",
+                "@type": [
+                  "enzml:BaseUnit"
+                ],
+                "kind": "mole",
+                "exponent": 1,
+                "scale": -3.0
+              },
+              {
+                "@context": {
+                  "enzml": "http://www.enzymeml.org/v2/",
+                  "OBO": "http://purl.obolibrary.org/obo/",
+                  "schema": "https://schema.org/"
+                },
+                "@id": "enzml:BaseUnit/c85ac147-42ac-40d6-bc03-172be2f0d7ad",
+                "@type": [
+                  "enzml:BaseUnit"
+                ],
+                "kind": "litre",
+                "exponent": -1,
+                "scale": 1.0
+              }
+            ]
+          },
+          "time_unit": {
+            "@context": {
+              "enzml": "http://www.enzymeml.org/v2/",
+              "OBO": "http://purl.obolibrary.org/obo/",
+              "schema": "https://schema.org/"
+            },
+            "@id": "OBO:UO_0000010",
+            "@type": [
+              "OBO:UO_0000000"
+            ],
+            "name": "s",
+            "base_units": [
+              {
+                "@context": {
+                  "enzml": "http://www.enzymeml.org/v2/",
+                  "OBO": "http://purl.obolibrary.org/obo/",
+                  "schema": "https://schema.org/"
+                },
+                "@id": "enzml:BaseUnit/8aec2395-2071-48e9-85ed-120847dfe64a",
+                "@type": [
+                  "enzml:BaseUnit"
+                ],
+                "kind": "second",
+                "exponent": 1,
+                "scale": 1.0
+              }
+            ]
+          },
+          "time": [
+            0.0,
+            1.0,
+            2.0,
+            3.0,
+            4.0,
+            5.0,
+            6.0,
+            7.0,
+            8.0,
+            9.0
+          ],
+          "data": [
+            0.0,
+            0.2,
+            0.4,
+            0.6000000000000001,
+            0.8,
+            1.0,
+            1.2000000000000002,
+            1.4000000000000001,
+            1.6,
+            1.8
+          ],
+          "is_calculated": false
+        },
+        {
+          "@context": {
+            "enzml": "http://www.enzymeml.org/v2/",
+            "OBO": "http://purl.obolibrary.org/obo/",
+            "schema": "https://schema.org/",
+            "species_id": {
+              "@type": "@id"
+            }
+          },
+          "@id": "enzml:MeasurementData/7af21a16-9cab-49e2-9250-278a4a57c91f",
+          "@type": [
+            "enzml:MeasurementData"
+          ],
+          "species_id": "s2",
+          "init_conc": 100.0,
+          "data_type": "conc",
+          "data_unit": {
+            "@context": {
+              "enzml": "http://www.enzymeml.org/v2/",
+              "OBO": "http://purl.obolibrary.org/obo/",
+              "schema": "https://schema.org/"
+            },
+            "@id": "OBO:UO_0000063",
+            "@type": [
+              "OBO:UO_0000000"
+            ],
+            "name": "mmol / l",
+            "base_units": [
+              {
+                "@context": {
+                  "enzml": "http://www.enzymeml.org/v2/",
+                  "OBO": "http://purl.obolibrary.org/obo/",
+                  "schema": "https://schema.org/"
+                },
+                "@id": "enzml:BaseUnit/b943545d-894b-445c-a745-c1215180ec8d",
+                "@type": [
+                  "enzml:BaseUnit"
+                ],
+                "kind": "mole",
+                "exponent": 1,
+                "scale": -3.0
+              },
+              {
+                "@context": {
+                  "enzml": "http://www.enzymeml.org/v2/",
+                  "OBO": "http://purl.obolibrary.org/obo/",
+                  "schema": "https://schema.org/"
+                },
+                "@id": "enzml:BaseUnit/c85ac147-42ac-40d6-bc03-172be2f0d7ad",
+                "@type": [
+                  "enzml:BaseUnit"
+                ],
+                "kind": "litre",
+                "exponent": -1,
+                "scale": 1.0
+              }
+            ]
+          },
+          "time_unit": {
+            "@context": {
+              "enzml": "http://www.enzymeml.org/v2/",
+              "OBO": "http://purl.obolibrary.org/obo/",
+              "schema": "https://schema.org/"
+            },
+            "@id": "OBO:UO_0000010",
+            "@type": [
+              "OBO:UO_0000000"
+            ],
+            "name": "s",
+            "base_units": [
+              {
+                "@context": {
+                  "enzml": "http://www.enzymeml.org/v2/",
+                  "OBO": "http://purl.obolibrary.org/obo/",
+                  "schema": "https://schema.org/"
+                },
+                "@id": "enzml:BaseUnit/8aec2395-2071-48e9-85ed-120847dfe64a",
+                "@type": [
+                  "enzml:BaseUnit"
+                ],
+                "kind": "second",
+                "exponent": 1,
+                "scale": 1.0
+              }
+            ]
+          },
+          "time": [
+            0.0,
+            1.0,
+            2.0,
+            3.0,
+            4.0,
+            5.0,
+            6.0,
+            7.0,
+            8.0,
+            9.0
+          ],
+          "data": [
+            100.0,
+            99.0,
+            98.0,
+            97.0,
+            96.0,
+            95.0,
+            94.0,
+            93.0,
+            92.0,
+            91.0
+          ],
+          "is_calculated": false
+        }
+      ]
+    }
+  ],
+  "equations": [],
+  "parameters": []
+}
\ No newline at end of file
diff --git a/tests/integration/__init__.py b/tests/integration/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/unit/__init__.py b/tests/unit/__init__.py
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/tests/unit/__init__.py
@@ -0,0 +1 @@
+
diff --git a/tests/unit/test_equations.py b/tests/unit/test_equations.py
new file mode 100644
index 0000000..3556555
--- /dev/null
+++ b/tests/unit/test_equations.py
@@ -0,0 +1,256 @@
+import pytest
+
+from pyenzyme.equations._math import build_equation, build_equations
+from pyenzyme.equations._chem import build_reaction, build_reactions
+from pyenzyme.units import M, second
+from pyenzyme.model import EquationType
+
+
+class TestMathEquations:
+    def test_parse_equation(self):
+        # Arrange
+        equation = "s1'(t) = kcat * p0(t) * s0(t)"
+
+        # Act
+        equation = build_equation(equation, unit=M / second)
+
+        # Assert
+        expected_vars = ["p0", "s0"]
+        expected_params = ["kcat"]
+
+        assert (
+            equation.species_id == "s1"
+        ), f"Species ID is not correct. Got {equation.species_id}"
+        assert (
+            equation.equation == "kcat*p0*s0"
+        ), "Equation is not correct. Got {equation.equation.equation}"
+        assert equation.parameters[0].name == "kcat", "Parameter name is not correct"
+        assert (
+            equation.parameters[0].symbol == "kcat"
+        ), "Parameter symbol is not correct"
+
+        for var in equation.variables:
+            assert var.name in expected_vars
+            assert var.symbol in expected_vars
+
+        for param in equation.parameters:
+            assert param.name in expected_params
+            assert param.symbol in expected_params
+
+    def test_invalid_equation_no_left(self):
+        # Arrange
+        equation = "kcat * p0(t) * s0(t)"
+
+        # Act
+        with pytest.raises(ValueError):
+            equation = build_equation(equation, unit=M / second)
+
+    def test_invalid_equation_no_right(self):
+        # Arrange
+        equation = "s1'(t) ="
+
+        # Act
+        with pytest.raises(ValueError):
+            equation = build_equation(equation, unit=M / second)
+
+    def test_invalid_equation_no_equals(self):
+        # Arrange
+        equation = "s1'(t) kcat * p0(t) * s0(t)"
+
+        # Act
+        with pytest.raises(ValueError):
+            equation = build_equation(equation, unit=M / second)
+
+    def test_equation_with_funs(self):
+        # Arrange
+        equation = "s1'(t) = kcat * exp(p0(t) * t)"
+
+        # Act
+        equation = build_equation(equation, unit=M / second)
+
+        # Assert
+        assert (
+            equation.species_id == "s1"
+        ), f"Species ID is not correct. Got {equation.species_id}"
+        assert (
+            equation.equation == "kcat*exp(p0*t)"
+        ), f"Equation is not correct. Got {equation.equation}"
+
+    def test_equation_with_fun_only_t(self):
+        # Arrange
+        equation = "s1'(t) = kcat * exp(t)"
+
+        # Act
+        equation = build_equation(equation, unit=M / second)
+
+        # Assert
+        assert (
+            equation.species_id == "s1"
+        ), f"Species ID is not correct. Got {equation.species_id}"
+        assert (
+            equation.equation == "kcat*exp(t)"
+        ), f"Equation is not correct. Got {equation.equation}"
+
+    def test_multiple_equations(self):
+        # Arrange
+        equations = [
+            "s1'(t) = kcat * E_tot * s0(t)",
+            "E_tot = p0(t) + p1(t)",
+        ]
+
+        # Act
+        units = [M / second, M]
+        equations = build_equations(*equations, units=units)
+
+        # Assert
+        assert len(equations) == 2, f"Expected 2 equations. Got {len(equations)}"
+
+    def test_init_assigment_equation(self):
+        # Arrange
+        equation = "E_tot = p0 + p1"
+
+        # Act
+        equation = build_equation(equation, unit=M)
+
+        # Assert
+        assert (
+            equation.species_id == "E_tot"
+        ), f"Species ID is not correct. Got {equation.species_id}"
+        assert (
+            equation.equation == "p0 + p1"
+        ), f"Equation is not correct. Got {equation.equation}"
+        assert (
+            equation.equation_type == EquationType.INITIAL_ASSIGNMENT
+        ), f"Equation type is not correct. Got {equation.equation_type}"
+
+    def test_assigment_equation(self):
+        # Arrange
+        equation = "E_tot(t) = p0 + p1"
+
+        # Act
+        equation = build_equation(equation, unit=M)
+
+        # Assert
+        assert (
+            equation.species_id == "E_tot"
+        ), f"Species ID is not correct. Got {equation.species_id}"
+        assert (
+            equation.equation == "p0 + p1"
+        ), f"Equation is not correct. Got {equation.equation}"
+        assert (
+            equation.equation_type == EquationType.ASSIGNMENT
+        ), f"Equation type is not correct. Got {equation.equation_type}"
+
+
+class TestChemEqautions:
+    def test_build_irrev_reaction(self):
+        # Arrange
+        reaction_str = "2 s1 + s2 -> 2 s3 + s4"
+
+        # Act
+        reac = build_reaction(
+            id="R1",
+            name="Reaction 1",
+            scheme=reaction_str,
+        )
+
+        # Assert
+        expected = [
+            (-2.0, "s1"),
+            (-1.0, "s2"),
+            (2.0, "s3"),
+            (1.0, "s4"),
+        ]
+
+        assert reac.id == "R1", f"Reaction ID is not correct. Got {reac.id}"
+        assert (
+            reac.name == "Reaction 1"
+        ), f"Reaction name is not correct. Got {reac.name}"
+
+        for stoich, species in expected:
+            element = next(
+                filter(lambda x: x.species_id == species, reac.species), None
+            )
+
+            if not element:
+                assert False, f"Species {species} not found in reaction"
+
+            assert (
+                element.stoichiometry == stoich
+            ), f"Stoichiometry for {species} is not correct. Got {element.stoichiometry}"
+
+            assert (
+                element.species_id == species
+            ), f"Species ID for {species} is not correct. Got {element.species_id}"
+
+    def test_build_rev_reaction(self):
+        # Arrange
+        reaction_str = "s1 + s2 <=> s3 + s4"
+
+        # Act
+        reac = build_reaction(
+            id="R1",
+            name="Reaction 1",
+            scheme=reaction_str,
+        )
+
+        # Assert
+        assert reac.reversible is True, "Reaction is not reversible"
+
+    def test_build_w_modifiers(self):
+        # Arrange
+        reaction_str = "s1 + s2 -> s3 + s4"
+
+        # Act
+        reac = build_reaction(
+            id="R1",
+            name="Reaction 1",
+            scheme=reaction_str,
+            modifiers=["s5", "s6"],
+        )
+
+        # Assert
+        assert (
+            len(reac.modifiers) == 2
+        ), f"Expected 2 modifiers. Got {len(reac.modifiers)}"
+
+    def test_build_invalid_reaction(self):
+        # Arrange
+        reaction_str = "s1 + s2 + s3"
+
+        # Act
+        with pytest.raises(ValueError):
+            build_reaction("R1", "Reaction 1", reaction_str)
+
+    def test_build_multiple_reactions(self):
+        # Arrange
+        reactions = [
+            "s1 + s2 -> s3 + s4",
+            "s2 -> s5",
+        ]
+
+        # Act
+        reacs = build_reactions(*reactions)
+
+        # Assert
+        assert len(reacs) == 2, f"Expected 2 reactions. Got {len(reacs)}"
+
+    def test_build_multiple_reactions_w_modifiers(self):
+        # Arrange
+        reactions = [
+            "s1 + s2 -> s3 + s4",
+            "s2 -> s5",
+        ]
+
+        # Act
+        modifiers = {"r1": ["p0"]}
+        reacs = build_reactions(*reactions, modifiers=modifiers)
+
+        # Assert
+        assert len(reacs) == 2, f"Expected 2 reactions. Got {len(reacs)}"
+
+        r0 = reacs[0]
+        assert len(r0.modifiers) == 1, f"Expected 1 modifier. Got {len(r0.modifiers)}"
+
+        r1 = reacs[1]
+        assert len(r1.modifiers) == 0, f"Expected 0 modifiers. Got {len(r1.modifiers)}"
diff --git a/tests/unit/test_tabular.py b/tests/unit/test_tabular.py
new file mode 100644
index 0000000..821faa3
--- /dev/null
+++ b/tests/unit/test_tabular.py
@@ -0,0 +1,147 @@
+import pytest
+import pandas as pd
+import pyenzyme as pe
+
+from pyenzyme.units import mM, s
+from pyenzyme.tabular import _measurement_to_pandas, to_pandas
+
+
+class TestTabularExport:
+    def test_single_measurement(self, measurement_valid):
+        """Test that a single measurement can be converted to a pandas DataFrame"""
+
+        # Act
+        df = _measurement_to_pandas(measurement_valid.measurements[0])
+
+        # Assert
+        assert isinstance(df, pd.DataFrame), f"Expected a DataFrame. Got {type(df)}"
+
+    def test_invalid_measurement(self, measurement_invalid):
+        """Test that an invalid measurement raises a ValueError"""
+
+        # Act
+        with pytest.raises(ValueError):
+            _measurement_to_pandas(measurement_invalid.measurements[0])
+
+    def test_multiple_measurements(self, measurement_valid):
+        """Test that multiple measurements can be converted to a pandas DataFrame"""
+
+        # Act
+        df = to_pandas(measurement_valid)
+
+        # Assert
+        total_time_len = sum(
+            [len(m.species[0].time) for m in measurement_valid.measurements]
+        )
+
+        assert (
+            df.shape[0] == total_time_len
+        ), f"Expected {total_time_len} rows. Got {df.shape[0]}"
+        assert df.shape[1] == 4, f"Expected 4 columns. Got {df.shape[1]}"
+        assert isinstance(df, pd.DataFrame), f"Expected a DataFrame. Got {type(df)}"
+        assert (
+            df["id"].nunique() == 2
+        ), f"Expected 2 unique IDs. Got {df['id'].nunique()}"
+
+        for measurement in measurement_valid.measurements:
+            df_sub = df[df["id"] == measurement.id]
+            assert df_sub.shape[0] == len(
+                measurement.species[0].time
+            ), f"Expected {len(measurement.species[0].time)} rows. Got {df_sub.shape[0]}"
+
+            for species in measurement.species:
+                assert (
+                    species.species_id in df.columns
+                ), f"Expected column for {species}"
+
+
+class TestTabularImport:
+    def test_csv_import(self):
+        """Test that a CSV file can be imported to a pandas DataFrame"""
+        # Act
+        meas = pe.read_csv("tests/fixtures/tabular/data.csv", data_unit=mM, time_unit=s)
+
+        # Assert
+        assert len(meas) == 2, f"Expected 2 measurements. Got {len(meas)}"
+
+        for m in meas:
+            assert len(m.species) == 2, f"Expected 2 species. Got {len(m.species)}"
+            assert (
+                len(m.species[0].time) == 11
+            ), f"Expected 10 time points. Got {len(m.species[0].time)}"
+            assert (
+                len(m.species[1].time) == 11
+            ), f"Expected 10 time points. Got {len(m.species[1].time)}"
+            assert (
+                m.species[0].data_unit == mM
+            ), f"Expected mM. Got {m.species[0].data_unit}"
+            assert (
+                m.species[0].time_unit == s
+            ), f"Expected s. Got {m.species[0].time_unit}"
+            assert (
+                m.species[1].data_unit == mM
+            ), f"Expected mM. Got {m.species[1].data_unit}"
+            assert (
+                m.species[1].time_unit == s
+            ), f"Expected s. Got {m.species[1].time_unit}"
+
+    def test_excel_import(self):
+        """Test that a Excel file can be imported to a pandas DataFrame"""
+        # Act
+        meas = pe.read_excel(
+            "tests/fixtures/tabular/data.xlsx", data_unit=mM, time_unit=s
+        )
+
+        # Assert
+        assert len(meas) == 2, f"Expected 2 measurements. Got {len(meas)}"
+
+        for m in meas:
+            assert len(m.species) == 2, f"Expected 2 species. Got {len(m.species)}"
+            assert (
+                len(m.species[0].time) == 11
+            ), f"Expected 10 time points. Got {len(m.species[0].time)}"
+            assert (
+                len(m.species[1].time) == 11
+            ), f"Expected 10 time points. Got {len(m.species[1].time)}"
+            assert (
+                m.species[0].data_unit == mM
+            ), f"Expected mM. Got {m.species[0].data_unit}"
+            assert (
+                m.species[0].time_unit == s
+            ), f"Expected s. Got {m.species[0].time_unit}"
+            assert (
+                m.species[1].data_unit == mM
+            ), f"Expected mM. Got {m.species[1].data_unit}"
+            assert (
+                m.species[1].time_unit == s
+            ), f"Expected s. Got {m.species[1].time_unit}"
+
+    def test_invalid_types(self):
+        """Test that an invalid CSV raises a ValueError"""
+        # Act
+        with pytest.raises(AssertionError):
+            pe.read_csv(
+                "tests/fixtures/tabular/data_invalid_chars.csv",
+                data_unit=mM,
+                time_unit=s,
+            )
+
+    def test_invalid_csv(self):
+        """Test that an invalid CSV raises a ValueError"""
+        # Act
+        with pytest.raises(AssertionError):
+            pe.read_csv(
+                "tests/fixtures/tabular/data_invalid.csv",
+                data_unit=mM,
+                time_unit=s,
+            )
+
+    def test_invalid_excel(self):
+        """Test that an invalid Excel raises a ValueError"""
+        # Act
+        with pytest.raises(AssertionError):
+            pe.read_excel(
+                "tests/fixtures/tabular/data_invalid.xlsx",
+                data_unit=mM,
+                time_unit=s,
+            )