Add unit tests for composite_snr()

tests/estimation/test_composite_snr.py

@@ -0,0 +1,62 @@
+import numpy as np
+
+import sdr
+
+
+def test_same():
+    snr1 = np.arange(-40, 40 + 10, 10)
+    snr = sdr.composite_snr(snr1, snr1)
+    snr_truth = np.array(
+        [
+            -76.99056855,
+            -56.99837726,
+            -37.07570176,
+            -17.7815125,
+            -1.76091259,
+            9.78810701,
+            19.97833938,
+            29.99782907,
+            39.99978286,
+        ]
+    )
+    assert np.allclose(snr, snr_truth)
+
+
+def test_different_n20():
+    snr1 = np.arange(-40, 40 + 10, 10)
+    snr2 = -20
+    snr = sdr.composite_snr(snr1, snr2)
+    snr_truth = np.array(
+        [
+            -57.03334375,
+            -47.0372116,
+            -37.07570176,
+            -27.44292983,
+            -20.02166062,
+            -17.40757323,
+            -17.03334375,
+            -16.9940842,
+            -16.99013866,
+        ]
+    )
+    assert np.allclose(snr, snr_truth)
+
+
+def test_different_20():
+    snr1 = np.arange(-40, 40 + 10, 10)
+    snr2 = 20
+    snr = sdr.composite_snr(snr1, snr2)
+    snr_truth = np.array(
+        [
+            -37.03291808,
+            -27.03295678,
+            -17.03334375,
+            -7.0372116,
+            2.92429824,
+            12.55707017,
+            19.97833938,
+            22.59242677,
+            22.96665625,
+        ]
+    )
+    assert np.allclose(snr, snr_truth)