Phase 2/4 done, working on phase 3/5

internal/datasource/epics/epics_test.go

@@ -0,0 +1,80 @@
+//go:build epics
+
+package epics_test
+
+import (
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/uopi/uopi/internal/datasource"
+	"github.com/uopi/uopi/internal/datasource/epics"
+)
+
+// TestIntegration_SubscribeAndMetadata is an integration test that requires:
+//   - EPICS_BASE to be set in the environment (i.e. EPICS Base is installed).
+//   - TEST_PV to name a readable EPICS PV accessible via Channel Access.
+//
+// It connects to the named PV, waits up to 5 seconds for at least one value
+// update, and then verifies that the metadata contains a unit string.
+func TestIntegration_SubscribeAndMetadata(t *testing.T) {
+	if os.Getenv("EPICS_BASE") == "" {
+		t.Skip("EPICS_BASE not set; skipping EPICS integration test")
+	}
+	pvName := os.Getenv("TEST_PV")
+	if pvName == "" {
+		t.Skip("TEST_PV not set; skipping EPICS integration test")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+	defer cancel()
+
+	ds := epics.New("", "") // rely on environment for CA addr list / EPICS_CA_ADDR_LIST
+	if err := ds.Connect(ctx); err != nil {
+		t.Fatalf("Connect: %v", err)
+	}
+
+	// Fetch metadata before subscribing so we exercise GetMetadata.
+	meta, err := ds.GetMetadata(ctx, pvName)
+	if err != nil {
+		t.Fatalf("GetMetadata(%q): %v", pvName, err)
+	}
+	t.Logf("metadata: name=%q unit=%q type=%v displayLow=%v displayHigh=%v writable=%v",
+		meta.Name, meta.Unit, meta.Type, meta.DisplayLow, meta.DisplayHigh, meta.Writable)
+
+	// Subscribe and wait for at least one value update within 5 seconds.
+	ch := make(chan datasource.Value, 8)
+	cancelSub, err := ds.Subscribe(ctx, pvName, ch)
+	if err != nil {
+		t.Fatalf("Subscribe(%q): %v", pvName, err)
+	}
+	defer cancelSub()
+
+	select {
+	case v := <-ch:
+		t.Logf("received value: ts=%v data=%v quality=%v", v.Timestamp, v.Data, v.Quality)
+		if v.Quality == datasource.QualityBad {
+			t.Errorf("expected QualityGood or QualityUncertain, got QualityBad")
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatal("timed out waiting for first value update from PV")
+	case <-ctx.Done():
+		t.Fatal("context expired before receiving a value")
+	}
+
+	// ListSignals should now return at least one entry (the one we just connected).
+	signals, err := ds.ListSignals(ctx)
+	if err != nil {
+		t.Fatalf("ListSignals: %v", err)
+	}
+	if len(signals) == 0 {
+		t.Error("ListSignals returned no signals after successful Subscribe")
+	}
+
+	// History should return ErrHistoryUnavailable when no archive URL is set.
+	_, err = ds.History(ctx, pvName, time.Now().Add(-time.Hour), time.Now(), 100)
+	if err != datasource.ErrHistoryUnavailable {
+		t.Errorf("History with no archive URL: want ErrHistoryUnavailable, got %v", err)
+	}
+}