basic tests

test/chromaprint_test.exs

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+defmodule ChromaprintTest do
+  use ExUnit.Case, async: true
+  import Bitwise
+  doctest Chromaprint
+
+  @sample_rate 44_100
+  # Chromaprint needs ~3+ seconds of audio to produce a fingerprint.
+  @duration_seconds 4
+
+  defp sine_pcm(freq_hz, duration_s, sample_rate) do
+    n = duration_s * sample_rate
+    two_pi = 2.0 * :math.pi()
+
+    for i <- 0..(n - 1), into: <<>> do
+      sample = trunc(:math.sin(two_pi * freq_hz * i / sample_rate) * 32_000)
+      <<sample::little-signed-16>>
+    end
+  end
+
+  test "library version is reported" do
+    assert is_binary(Chromaprint.version())
+    assert byte_size(Chromaprint.version()) > 0
+  end
+
+  test "lists supported algorithms" do
+    assert :test2 in Chromaprint.algorithms()
+  end
+
+  describe "streaming API" do
+    setup do
+      {:ok, pcm: sine_pcm(440, @duration_seconds, @sample_rate)}
+    end
+
+    test "produces a non-empty fingerprint for a sine wave", %{pcm: pcm} do
+      {:ok, ctx} = Chromaprint.new()
+      :ok = Chromaprint.start(ctx, sample_rate: @sample_rate, channels: 1)
+      :ok = Chromaprint.feed(ctx, pcm)
+      :ok = Chromaprint.finish(ctx)
+      assert {:ok, fp} = Chromaprint.fingerprint(ctx)
+      assert is_binary(fp)
+      assert byte_size(fp) > 0
+    end
+
+    test "raw fingerprint is a non-empty list of uint32", %{pcm: pcm} do
+      {:ok, ctx} = Chromaprint.new()
+      :ok = Chromaprint.start(ctx, sample_rate: @sample_rate, channels: 1)
+      :ok = Chromaprint.feed(ctx, pcm)
+      :ok = Chromaprint.finish(ctx)
+      assert {:ok, raw} = Chromaprint.raw_fingerprint(ctx)
+      assert is_list(raw)
+      assert length(raw) > 0
+      assert Enum.all?(raw, fn x -> is_integer(x) and x >= 0 and x < 1 <<< 32 end)
+    end
+
+    test "hash returns a 32-bit unsigned integer", %{pcm: pcm} do
+      {:ok, ctx} = Chromaprint.new()
+      :ok = Chromaprint.start(ctx, sample_rate: @sample_rate, channels: 1)
+      :ok = Chromaprint.feed(ctx, pcm)
+      :ok = Chromaprint.finish(ctx)
+      assert {:ok, h} = Chromaprint.hash(ctx)
+      assert is_integer(h) and h >= 0 and h < 1 <<< 32
+    end
+  end
+
+  describe "compute/2 one-shot" do
+    test "matches the streaming result on the same input" do
+      pcm = sine_pcm(440, @duration_seconds, @sample_rate)
+
+      {:ok, ctx} = Chromaprint.new()
+      :ok = Chromaprint.start(ctx, sample_rate: @sample_rate, channels: 1)
+      :ok = Chromaprint.feed(ctx, pcm)
+      :ok = Chromaprint.finish(ctx)
+      {:ok, streamed} = Chromaprint.fingerprint(ctx)
+
+      assert {:ok, ^streamed} =
+               Chromaprint.compute(pcm, sample_rate: @sample_rate, channels: 1)
+    end
+  end
+
+  describe "encode/2 and decode/2 round-trip" do
+    test "raw → encode → decode → raw" do
+      pcm = sine_pcm(440, @duration_seconds, @sample_rate)
+      {:ok, ctx} = Chromaprint.new()
+      :ok = Chromaprint.start(ctx, sample_rate: @sample_rate, channels: 1)
+      :ok = Chromaprint.feed(ctx, pcm)
+      :ok = Chromaprint.finish(ctx)
+      {:ok, raw} = Chromaprint.raw_fingerprint(ctx)
+      {:ok, fp} = Chromaprint.fingerprint(ctx)
+
+      assert {:ok, ^fp} = Chromaprint.encode(raw, algorithm: :test2, base64: true)
+      assert {:ok, %{algorithm: :test2, raw: ^raw}} = Chromaprint.decode(fp)
+    end
+  end
+end