feat(brain): add Query client for skill handler context injection

internal/brain/client_test.go

@@ -0,0 +1,67 @@
+package brain_test
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/mathiasbq/supervisor/internal/brain"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestQueryEmptyBaseURL(t *testing.T) {
+	result, err := brain.Query(context.Background(), "", "tdd patterns", 3)
+	require.NoError(t, err)
+	assert.Empty(t, result)
+}
+
+func TestQueryEmptyQuery(t *testing.T) {
+	result, err := brain.Query(context.Background(), "http://localhost:9999", "", 3)
+	require.NoError(t, err)
+	assert.Empty(t, result)
+}
+
+func TestQueryFormatsResults(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/query", r.URL.Path)
+		var req map[string]any
+		require.NoError(t, json.NewDecoder(r.Body).Decode(&req))
+		assert.Equal(t, "tdd patterns", req["query"])
+
+		json.NewEncoder(w).Encode(map[string]any{ //nolint:errcheck
+			"results": []map[string]any{
+				{"path": "knowledge/tdd.md", "title": "TDD Guide", "excerpt": "Always write tests first.", "score": 5},
+				{"path": "knowledge/go.md", "title": "Go Conventions", "excerpt": "Use table-driven tests.", "score": 3},
+			},
+		})
+	}))
+	defer srv.Close()
+
+	result, err := brain.Query(context.Background(), srv.URL, "tdd patterns", 3)
+	require.NoError(t, err)
+	assert.Contains(t, result, "## Relevant knowledge")
+	assert.Contains(t, result, "TDD Guide")
+	assert.Contains(t, result, "Always write tests first.")
+	assert.Contains(t, result, "Go Conventions")
+}
+
+func TestQueryEmptyResults(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewEncoder(w).Encode(map[string]any{"results": []any{}}) //nolint:errcheck
+	}))
+	defer srv.Close()
+
+	result, err := brain.Query(context.Background(), srv.URL, "obscure query", 3)
+	require.NoError(t, err)
+	assert.Empty(t, result)
+}
+
+func TestQueryUnavailableServerReturnsEmpty(t *testing.T) {
+	// Brain unavailable — should degrade gracefully, no error
+	result, err := brain.Query(context.Background(), "http://127.0.0.1:19999", "query", 3)
+	require.NoError(t, err)
+	assert.Empty(t, result)
+}