tests/test_encoder.py

import numpy as np
from src.hdc_encoder.encoder import encode, DIM

class TestHDCEncoder:
    def setup_method(self):
        """Initialize base parameters before each test to guarantee state isolation."""
        self.prosody = {"pitch": 140.0, "energy": 0.25, "tempo": 115.0, "pause_ratio": 0.15}
        self.frames = 40
        self.mfcc = np.random.rand(13, self.frames).astype(np.float32)

    def test_encoder_dimensionality(self):
        """Verify the output vector matches the strict dimensional parameters."""
        hv = encode(self.mfcc, self.prosody)
        
        assert hv.shape == (DIM,), f"Dimensionality failure: Expected {DIM}, got {hv.shape[0]}"
        assert hv.dtype == np.uint8, f"Type architecture failure: Expected uint8, got {hv.dtype}"

    def test_temporal_sequence_asymmetry(self):
        """
        Verify that reversing the audio sequence produces a fundamentally different 
        hypervector. This proves the encoder captures the temporal direction of speech.
        """
        mfcc_reversed = self.mfcc[:, ::-1]
        
        hv_forward = encode(self.mfcc, self.prosody)
        hv_reversed = encode(mfcc_reversed, self.prosody)
        
        similarity = np.mean(hv_forward == hv_reversed)
        
        # In an orthogonal 10k dimensional space, random vectors share ~50% similarity.
        # We enforce a strict threshold to ensure the temporal shift breaks vector alignment.
        assert similarity < 0.60, f"Commutativity failure: Temporal sequence not isolated. Similarity: {similarity}"

    def test_prosody_modulation(self):
        """Verify that altering emotional/prosodic intent alters the final memory vector."""
        angry_prosody = {"pitch": 240.0, "energy": 0.85, "tempo": 160.0, "pause_ratio": 0.05}
        
        hv_base = encode(self.mfcc, self.prosody)
        hv_angry = encode(self.mfcc, angry_prosody)
        
        similarity = np.mean(hv_base == hv_angry)
        
        assert similarity < 0.95, "Modulation failure: Prosody shifts did not impact the spatial vector."