Make Groups renderable (#181)

This change makes the result of `Group` renderable directly, instead of
panicking, with the important caveat that root-level attributes are
_ignored_. I don't think this will give problems in practice, as the
main use case for rendering `Group` is basically to return root-level
elements to the client using something like HTMX.

I tried adding a `Fragment`, but it was weird and confusing having two
functions (`Group` and `Fragment`) do essentially the same thing, the
only difference being whether the argument was a slice of `Node`s or
varargs.

Fixes #162

1 files changed, 27 insertions, 22 deletions

diff --git a/gomponents_test.go b/gomponents_test.go
index c0ae7a7..f3e81b0 100644
--- a/gomponents_test.go
+++ b/gomponents_test.go
@@ -234,35 +234,40 @@ func TestGroup(t *testing.T) {
 		assert.Equal(t, `<div class="foo"><img><br id="hat"><hr></div>`, e)
 	})
 
-	t.Run("panics on direct render", func(t *testing.T) {
-		e := g.Group(nil)
-		panicked := false
-		defer func() {
-			if err := recover(); err != nil {
-				panicked = true
-			}
-		}()
-		_ = e.Render(nil)
-		if !panicked {
-			t.FailNow()
-		}
+	t.Run("ignores attributes at the first level", func(t *testing.T) {
+		children := []g.Node{g.Attr("class", "hat"), g.El("div"), g.El("span")}
+		e := g.Group(children)
+		assert.Equal(t, "<div></div><span></span>", e)
 	})
 
-	t.Run("panics on direct string", func(t *testing.T) {
-		e := g.Group(nil).(fmt.Stringer)
-		panicked := false
-		defer func() {
-			if err := recover(); err != nil {
-				panicked = true
-			}
-		}()
-		_ = e.String()
-		if !panicked {
+	t.Run("does not ignore attributes at the second level", func(t *testing.T) {
+		children := []g.Node{g.El("div", g.Attr("class", "hat")), g.El("span")}
+		e := g.Group(children)
+		assert.Equal(t, `<div class="hat"></div><span></span>`, e)
+	})
+
+	t.Run("can render a group child node including attributes", func(t *testing.T) {
+		children := []g.Node{g.Attr("id", "hat"), g.El("div"), g.El("span")}
+		e := g.El("div", g.Group(children))
+		assert.Equal(t, `<div id="hat"><div></div><span></span></div>`, e)
+	})
+
+	t.Run("implements fmt.Stringer", func(t *testing.T) {
+		children := []g.Node{g.El("div"), g.El("span")}
+		e := g.Group(children)
+		if e, ok := e.(fmt.Stringer); !ok || e.String() != "<div></div><span></span>" {
 			t.FailNow()
 		}
 	})
 }
 
+func ExampleGroup() {
+	children := []g.Node{g.El("div"), g.El("span")}
+	e := g.Group(children)
+	_ = e.Render(os.Stdout)
+	// Output: <div></div><span></span>
+}
+
 func TestIf(t *testing.T) {
 	t.Run("returns node if condition is true", func(t *testing.T) {
 		n := g.El("div", g.If(true, g.El("span")))