Add some tests for nested empty arrays

lexer_test.go

diff --git a/lexer_test.go b/lexer_test.go
index b7de9f5..1d7e37b 100644
--- a/lexer_test.go
+++ b/lexer_test.go
@@ -300,6 +300,20 @@
 	})
 }
 
+func TestNestedArrays(t *testing.T) {
+	testFlow(t, "foo = [[[]]]", []token{
+		token{tokenKey, "foo"},
+		token{tokenEqual, "="},
+		token{tokenLeftBracket, "["},
+		token{tokenLeftBracket, "["},
+		token{tokenLeftBracket, "["},
+		token{tokenRightBracket, "]"},
+		token{tokenRightBracket, "]"},
+		token{tokenRightBracket, "]"},
+		token{tokenEOF, ""},
+	})
+}
+
 func TestKeyEqualNumber(t *testing.T) {
 	testFlow(t, "foo = 42", []token{
 		token{tokenKey, "foo"},

parser_test.go

diff --git a/parser_test.go b/parser_test.go
index 9beef36..9108bab 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -142,6 +142,13 @@
 	})
 }
 
+func TestNestedEmptyArrays(t *testing.T) {
+	tree, err := Load("a = [[[]]]")
+	assertTree(t, tree, err, map[string]interface{}{
+		"a": [][][]interface{}{[][]interface{}{[]interface{}{}}},
+	})
+}
+
 func TestArrayMixedTypes(t *testing.T) {
 	_, err := Load("a = [42, 16.0]")
 	if err.Error() != "mixed types in array" {