feat(embedding): 嵌入（n-gram 哈希向量 + 关键词 FTS + OpenAI 兼容 API 钩子 + Manager 选择）

internal/runtime/embedding/ngram_test.go

@@ -0,0 +1,155 @@
+package embedding
+
+import (
+	"context"
+	"math"
+	"testing"
+)
+
+func TestNGramEmbedder_Dim(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(128)
+	if got := e.Dim(); got != 128 {
+		t.Fatalf("Dim() = %d, want 128", got)
+	}
+}
+
+func TestNGramEmbedder_DefaultDim(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(0)
+	if got := e.Dim(); got != defaultNGramDim {
+		t.Fatalf("Dim() = %d, want defaultNGramDim (%d)", got, defaultNGramDim)
+	}
+}
+
+func TestNGramEmbedder_VectorLengthMatchesDim(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(64)
+	vectors, err := e.Embed(context.Background(), []string{"alpha", "beta gamma"})
+	if err != nil {
+		t.Fatalf("Embed() error: %v", err)
+	}
+	if len(vectors) != 2 {
+		t.Fatalf("got %d vectors, want 2", len(vectors))
+	}
+	for i, v := range vectors {
+		if got := len(v); got != e.Dim() {
+			t.Errorf("vector %d length = %d, want %d", i, got, e.Dim())
+		}
+	}
+}
+
+func TestNGramEmbedder_Deterministic(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(128)
+	ctx := context.Background()
+	texts := []string{"hello world", "the quick brown fox jumps", "Golang embedding"}
+
+	first, err := e.Embed(ctx, texts)
+	if err != nil {
+		t.Fatalf("Embed() error: %v", err)
+	}
+	second, err := e.Embed(ctx, texts)
+	if err != nil {
+		t.Fatalf("Embed() error: %v", err)
+	}
+	if len(first) != len(second) {
+		t.Fatalf("got %d vectors on first call, %d on second", len(first), len(second))
+	}
+	for i := range first {
+		if !equalVector(first[i], second[i]) {
+			t.Fatalf("vector %d differs between calls", i)
+		}
+	}
+}
+
+func TestNGramEmbedder_Normalized(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(128)
+	vectors, err := e.Embed(context.Background(), []string{
+		"a",
+		"the quick brown fox jumps over the lazy dog",
+		"golang fts embedding test",
+	})
+	if err != nil {
+		t.Fatalf("Embed() error: %v", err)
+	}
+	for i, v := range vectors {
+		norm := l2Norm(v)
+		if math.Abs(norm-1) > 1e-6 {
+			t.Errorf("vector %d L2 norm = %f, want 1", i, norm)
+		}
+	}
+}
+
+func TestNGramEmbedder_DifferentTextsDiffer(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(128)
+	vectors, err := e.Embed(context.Background(), []string{"dog", "cat", "astronaut"})
+	if err != nil {
+		t.Fatalf("Embed() error: %v", err)
+	}
+	if len(vectors) != 3 {
+		t.Fatalf("got %d vectors, want 3", len(vectors))
+	}
+	for i := 0; i < len(vectors); i++ {
+		if l2Norm(vectors[i]) == 0 {
+			t.Errorf("vector %d is a zero vector", i)
+		}
+		for j := i + 1; j < len(vectors); j++ {
+			if equalVector(vectors[i], vectors[j]) {
+				t.Errorf("vectors %d and %d are identical", i, j)
+			}
+		}
+	}
+}
+
+func TestNGramEmbedder_EmptyInput(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(128)
+	vectors, err := e.Embed(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("Embed(nil) error: %v", err)
+	}
+	if len(vectors) != 0 {
+		t.Errorf("got %d vectors, want 0", len(vectors))
+	}
+}
+
+func TestNGramEmbedder_CanceledContext(t *testing.T) {
+	t.Parallel()
+
+	e := NewNGram(128)
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	if _, err := e.Embed(ctx, []string{"hello"}); err == nil {
+		t.Fatal("expected error on canceled context, got nil")
+	}
+}
+
+func equalVector(a, b Vector) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func l2Norm(v Vector) float64 {
+	var sum float64
+	for _, x := range v {
+		sum += float64(x) * float64(x)
+	}
+	return math.Sqrt(sum)
+}