fix: add minimum input length guards to all test modules

Complexity.py

@@ -75,7 +75,7 @@ def linear_complexity_test(binary_data:str, verbose=False, block_size=500):
 
             return (p_value, (p_value >= 0.01))
         else:
-            return (-1.0, False)
+            return (0.0, False, 'Error: Not enough data to run this test. Minimum input length is {} bits (2 blocks of {}).'.format(2 * block_size, block_size))
 
     @staticmethod
     def berlekamp_massey_algorithm(block_data):

Matrix.py

@@ -78,4 +78,4 @@ def binary_matrix_rank_text(binary_data:str, verbose=False, rows_in_matrix = 32,
 
             return (p_value, (p_value >= 0.01))
         else:
-            return (-1.0, False)
+            return (0.0, False, 'Error: Not enough data to run this test. Minimum input length is 1024 bits (32x32 matrix).')

RandomExcursions.py

@@ -60,6 +60,10 @@ def random_excursions_test(binary_data:str, verbose=False, state=1):
             cycles.append(cumulative_sum[position[pos]:position[pos + 1] + 1])
         num_cycles = len(cycles)
 
+        if num_cycles == 0:
+            states = ['-4', '-3', '-2', '-1', '+1', '+2', '+3', '+4']
+            return [(states[i], x_values[i], 0.0, 0.0, False) for i in range(len(x_values))]
+
         state_count = []
         for cycle in cycles:
             # Determine the number of times each cycle visits each state

Spectral.py

@@ -23,6 +23,10 @@ def spectral_test(binary_data:str, verbose=False):
         :return:    (p_value, bool)     A tuple which contain the p_value and result of frequency_test(True or False)
         """
         length_of_binary_data = len(binary_data)
+
+        if length_of_binary_data < 1000:
+            return (0.0, False, 'Error: Not enough data to run this test. Minimum input length is 1000 bits.')
+
         plus_one_minus_one = []
 
         # Step 1 - The zeros and ones of the input sequence (ε) are converted to values of –1 and +1

TemplateMatching.py

@@ -27,6 +27,10 @@ def non_overlapping_test(binary_data:str, verbose=False, template_pattern='00000
 
         length_of_binary = len(binary_data)
         pattern_size = len(template_pattern)
+
+        if length_of_binary < block * pattern_size:
+            return (0.0, False, 'Error: Not enough data to run this test. Minimum input length is {} bits.'.format(block * pattern_size))
+
         block_size = floor(length_of_binary / block)
         pattern_counts = zeros(block)
 
@@ -89,6 +93,10 @@ def overlapping_patterns(binary_data:str, verbose=False, pattern_size=9, block_s
         :return:    (p_value, bool) A tuple which contain the p_value and result of frequency_test(True or False)
         """
         length_of_binary_data = len(binary_data)
+
+        if length_of_binary_data < block_size:
+            return (0.0, False, 'Error: Not enough data to run this test. Minimum input length is {} bits.'.format(block_size))
+
         pattern = ''
         for count in range(pattern_size):
             pattern += '1'