diff --git a/tests/pargen/test_extract_tau.py b/tests/pargen/test_extract_tau.py
new file mode 100644
index 000000000..efe718ef1
--- /dev/null
+++ b/tests/pargen/test_extract_tau.py
@@ -0,0 +1,172 @@
+import numpy as np
+import pytest
+from lgdo import Array, ArrayOfEqualSizedArrays, Table, WaveformTable
+
+from pygama.pargen import extract_tau
+
+
+def test_tp100_align():
+    """
+    Generate synthetic waveforms with random tp100s, then ensure that this function aligns all tp100s at the same sample
+    """
+    np.random.seed(42)
+    tp100_known = np.random.randint(3000, 3200, 1000)
+
+    tau = 30000
+    wf_len = 8192
+
+    test_wfs = []
+    for i in range(len(tp100_known)):
+        xs = np.arange(0, wf_len - tp100_known[i])
+        ys = extract_tau.one_exp(xs, tau, 1)
+        test_wfs.append(np.insert(ys, 0, np.zeros(tp100_known[i])))
+
+    superpulse_window_width = 13
+
+    time_aligned_wfs = extract_tau.tp100_align(
+        test_wfs, superpulse_window_width, tp100_known
+    )
+    tp100s = []
+    for wf in time_aligned_wfs:
+        tp100s.append(np.argmax(wf))
+    assert np.array_equal(
+        np.array(tp100s), np.full(len(tp100s), np.median(tp100_known) - 13)
+    )
+    assert len(time_aligned_wfs[0]) == 8192 - 2 * 13
+
+
+def test_dpz_model_fit():
+    tau2 = 30000
+    tau1 = 1100
+    frac = 0.98
+    wf_len = 8192
+    tp0 = 3200
+
+    xs = np.arange(0, wf_len - tp0)
+    ys = extract_tau.dpz_model(xs, 1000, tau1, tau2, frac)
+    test_wf = np.insert(ys, 0, np.zeros(tp0))
+    tau1_fit, tau2_fit, frac_fit, plot_dict_out = extract_tau.dpz_model_fit(
+        test_wf, percent_tau1_fit=0.1, percent_tau2_fit=0.2, idx_shift=2, plot=0
+    )
+
+    assert np.allclose(tau1, tau1_fit, rtol=1e-2)
+    assert np.allclose(tau2, tau2_fit, rtol=1e-2)
+    assert np.allclose(frac, frac_fit, rtol=1e-2)
+
+
+@pytest.mark.filterwarnings("ignore::RuntimeWarning")
+def test_get_dpz_decay_constants():
+    """
+    First, generate a fake HPGe energy spectrum and associated waveforms. Then extract the time constants from the waveforms associated with the 2615 peak
+    """
+    np.random.seed(42)
+    tau2 = 30000
+    tau1 = 1100
+    frac = 0.98
+    wf_len = 8192
+    tp0 = 3200
+    num_wfs = 1000
+
+    # Make the waveforms and then the lgdo table
+    # peaks = np.array([238.632, 583.191, 727.330, 860.564, 1620.5, 2103.53, 2614.553])
+    # daq_energies = []
+    # for peak in peaks:
+    #     daq_energies.extend(np.random.normal(peak, 10, num_wfs_per_peak).astype(int))
+
+
+    daq_energies = np.random.normal(2614.553, 10, num_wfs).astype(int)
+
+    wfs = []
+    for amplitude in daq_energies:
+        xs = np.arange(0, wf_len - tp0)
+        ys = extract_tau.dpz_model(xs, amplitude, tau1, tau2, frac)
+        test_wf = np.insert(ys, 0, np.zeros(tp0))
+        wfs.append(test_wf)
+
+    wf_tb = WaveformTable(
+        dt=np.full(len(wfs), 16),
+        dt_units="ns",
+        t0=np.full(len(wfs), 0),
+        t0_units="ns",
+        values=ArrayOfEqualSizedArrays(nda=np.array(wfs)),
+        values_units="ADC",
+    )
+    tb_data = Table(size=len(wfs))
+    tb_data.add_column(name="daqenergy", obj=Array(daq_energies))
+    tb_data.add_column(name="waveform", obj=wf_tb)
+
+    assert isinstance(tb_data["waveform"]["values"], ArrayOfEqualSizedArrays)
+
+    dpz_opt_dsp_dict = dict(
+        {
+            "outputs": ["tau1", "tau2", "frac"],
+            "processors": {
+                "bl_mean , bl_std, bl_slope, bl_intercept": {
+                    "function": "linear_slope_fit",
+                    "module": "dspeed.processors",
+                    "args": [
+                        "waveform[0:200]",
+                        "bl_mean",
+                        "bl_std",
+                        "bl_slope",
+                        "bl_intercept",
+                    ],
+                    "unit": ["ADC", "ADC", "ADC", "ADC"],
+                },
+                "wf_bl": {
+                    "function": "bl_subtract",
+                    "module": "dspeed.processors",
+                    "args": ["waveform", "bl_mean", "wf_bl"],
+                    "unit": "ADC",
+                },
+                "tau1, tau2, frac": {
+                    "function": "optimize_2pz",
+                    "module": "dspeed.processors",
+                    "args": [
+                        "waveform",
+                        "bl_mean",
+                        "round(52*us/waveform.period)",
+                        "len(waveform)",
+                        "db.dpz.tau1",
+                        "db.dpz.tau2",
+                        "db.dpz.frac",
+                        "tau1",
+                        "tau2",
+                        "frac",
+                    ],
+                    "defaults": {
+                        "db.dpz.tau1": 900,
+                        "db.dpz.tau2": 28000,
+                        "db.dpz.frac": 0.9855024553225362,
+                    },
+                },
+            },
+        }
+    )
+    
+    wf_field = "waveform"
+    percent_tau1_fit = 0.1
+    percent_tau2_fit = 0.2
+    offset_from_wf_max = 2
+    superpulse_bl_idx = 25
+    superpulse_window_width = 13
+    display = 0
+
+    tau = extract_tau.ExtractTau(dpz_opt_dsp_dict, wf_field)
+
+    tau.get_dpz_decay_constants(
+        tb_data,
+        percent_tau1_fit,
+        percent_tau2_fit,
+        offset_from_wf_max,
+        superpulse_bl_idx,
+        superpulse_window_width,
+        display,
+    )
+    assert np.allclose(
+        float(tau.output_dict["dpz"]["tau1"].split("*")[0]) / 16, tau1, rtol=1e-2
+    )
+    assert np.allclose(
+        float(tau.output_dict["dpz"]["tau2"].split("*")[0]) / 16, tau2, rtol=1e-2
+    )
+    assert np.allclose(float(tau.output_dict["dpz"]["frac"]), frac, rtol=1e-2)