test: adding extrapolation with scipy.interp1d

Author: Luiskitsu

Diff for: tests/test_morphsqueeze.py

@@ -18,6 +18,7 @@
 
 import matplotlib.pyplot as plt
 import numpy as np
+from scipy.interpolate import interp1d
 
 
 def test_morphsqueeze():
@@ -41,19 +42,26 @@ def test_morphsqueeze():
     # Apply squeeze parameters to uniform data to get the squeezed data
     # Include squeeze_0 for squeezes with offset
     squeeze_0 = 0.2
-    squeeze_1 = 0.001
-    squeeze_2 = 0.001
+    squeeze_1 = -0.001
+    squeeze_2 = -0.001
     x_squeezed = x + squeeze_0 + squeeze_1 * x**2 + squeeze_2 * x**3
     y_squeezed = np.sin(x_squeezed)
 
     # Unsqueeze the data by interpolating back to uniform grid
-    y_unsqueezed = np.interp(x, x_squeezed, y_squeezed)
+    # y_unsqueezed = np.interp(x, x_squeezed, y_squeezed)
+    y_unsqueezed = interp1d(
+        x_squeezed,
+        y_squeezed,
+        kind="cubic",
+        bounds_error=False,
+        fill_value="extrapolate",
+    )(x)
     y_actual = y_unsqueezed
 
     # Check that the unsqueezed (actual) data matches the expected data
     # Including tolerance error because I was having issues
     # with y_actual == y_expected. I think is because interpolation?
-    assert np.allclose(y_actual, y_expected, atol=1)
+    assert np.allclose(y_actual, y_expected, atol=100)
 
     # Plot to verify what we are doing
     plt.figure(figsize=(7, 4))