Add get_extended_sample_count unit tests

specs/_features/eip7594/das-core.md

@@ -215,7 +215,11 @@ def get_extended_sample_count(allowed_failures: uint64) -> uint64:
         return r
 
     def hypergeom_cdf(k, M, n, N):
-        return sum([math_comb(n, i) * math_comb(M - n, N - i) / math_comb(M, N)
+        k = int(k)
+        M = int(M)
+        n = int(n)
+        N = int(N)
+        return sum([math_comb(n, i) * math_comb(M - n, N - i) // math_comb(M, N)
                     for i in range(k + 1)])
 
     worst_case_missing = NUMBER_OF_COLUMNS // 2 + 1

tests/core/pyspec/eth2spec/test/eip7594/unittests/das/test_das.py

@@ -1,5 +1,6 @@
 import random
 from eth2spec.test.context import (
+    expect_assertion_error,
     spec_test,
     single_phase,
     with_eip7594_and_later,
@@ -67,3 +68,54 @@ def test_recover_matrix(spec):
     recovered_matrix = spec.recover_matrix(cells_dict, blob_count)
     flatten_original_cells = [cell for cells in original_cells for cell in cells]
     assert recovered_matrix == flatten_original_cells
+
+
+@with_eip7594_and_later
+@spec_test
+@single_phase
+def test_get_extended_sample_count__1(spec):
+    rng = random.Random(1111)
+    allowed_failures = rng.randint(0, spec.config.NUMBER_OF_COLUMNS // 2)
+    spec.get_extended_sample_count(allowed_failures)
+
+
+@with_eip7594_and_later
+@spec_test
+@single_phase
+def test_get_extended_sample_count__2(spec):
+    rng = random.Random(2222)
+    allowed_failures = rng.randint(0, spec.config.NUMBER_OF_COLUMNS // 2)
+    spec.get_extended_sample_count(allowed_failures)
+
+
+@with_eip7594_and_later
+@spec_test
+@single_phase
+def test_get_extended_sample_count__3(spec):
+    rng = random.Random(3333)
+    allowed_failures = rng.randint(0, spec.config.NUMBER_OF_COLUMNS // 2)
+    spec.get_extended_sample_count(allowed_failures)
+
+
+@with_eip7594_and_later
+@spec_test
+@single_phase
+def test_get_extended_sample_count__lower_bound(spec):
+    allowed_failures = 0
+    spec.get_extended_sample_count(allowed_failures)
+
+
+@with_eip7594_and_later
+@spec_test
+@single_phase
+def test_get_extended_sample_count__upper_bound(spec):
+    allowed_failures = spec.config.NUMBER_OF_COLUMNS // 2
+    spec.get_extended_sample_count(allowed_failures)
+
+
+@with_eip7594_and_later
+@spec_test
+@single_phase
+def test_get_extended_sample_count__upper_bound_exceed(spec):
+    allowed_failures = spec.config.NUMBER_OF_COLUMNS // 2 + 1
+    expect_assertion_error(lambda: spec.get_extended_sample_count(allowed_failures))