Added a /conditions/current endpoint with computed best-guess values for current conditions

internal/application/units/registry_test.go

@@ -0,0 +1,62 @@
+package units
+
+import "testing"
+
+func TestRegistryResolve(t *testing.T) {
+	reg := NewRegistry()
+	if err := reg.Register(StaticFactory{UnitSystem: "us", Converter: USConverter{}}); err != nil {
+		t.Fatalf("register us: %v", err)
+	}
+	if err := reg.Register(StaticFactory{UnitSystem: "metric", Converter: MetricConverter{}}); err != nil {
+		t.Fatalf("register metric: %v", err)
+	}
+
+	converter, err := reg.Resolve("US")
+	if err != nil {
+		t.Fatalf("resolve us: %v", err)
+	}
+	if converter.System() != "us" {
+		t.Fatalf("expected us converter, got %q", converter.System())
+	}
+
+	converter, err = reg.Resolve(" metric ")
+	if err != nil {
+		t.Fatalf("resolve metric: %v", err)
+	}
+	if converter.System() != "metric" {
+		t.Fatalf("expected metric converter, got %q", converter.System())
+	}
+}
+
+func TestRegistryRejectsInvalidRegistration(t *testing.T) {
+	reg := NewRegistry()
+	if err := reg.Register(nil); err == nil {
+		t.Fatalf("expected error for nil factory")
+	}
+
+	if err := reg.Register(StaticFactory{UnitSystem: "", Converter: USConverter{}}); err == nil {
+		t.Fatalf("expected error for empty unit system")
+	}
+
+	if err := reg.Register(StaticFactory{UnitSystem: "us", Converter: nil}); err == nil {
+		t.Fatalf("expected error for nil converter")
+	}
+
+	if err := reg.Register(StaticFactory{UnitSystem: "us", Converter: USConverter{}}); err != nil {
+		t.Fatalf("register us: %v", err)
+	}
+	if err := reg.Register(StaticFactory{UnitSystem: "US", Converter: USConverter{}}); err == nil {
+		t.Fatalf("expected duplicate registration error")
+	}
+}
+
+func TestRegistryResolveUnknown(t *testing.T) {
+	reg := NewRegistry()
+	if err := reg.Register(StaticFactory{UnitSystem: "us", Converter: USConverter{}}); err != nil {
+		t.Fatalf("register us: %v", err)
+	}
+
+	if _, err := reg.Resolve("metric"); err == nil {
+		t.Fatalf("expected unsupported unit system error")
+	}
+}