From 2759894ed838b7a30749827b63aa06c0ff98c391 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Mon, 9 Sep 2024 15:13:37 -0600
Subject: [PATCH] Factored out Slice failure assertions

---
 parser_test.go | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/parser_test.go b/parser_test.go
index babbe67..986279e 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -23,27 +23,30 @@ func hasPrefix(prefix []byte) func([]byte) bool {
 }
 
 func TestSlice(t *testing.T) {
+	assertParseFails := func(t rapid.TB, input []byte, p gigaparsec.Parser[byte, []byte]) (parseErr gigaparsec.ParseError) {
+		t.Helper()
+		start := gigaparsec.MakeState(cursor.NewSlice(input))
+		consumed, result, err := p(start)
+		test.ErrorAs(t, err, &parseErr, test.Sprint("expected ParseError"))
+		test.False(t, consumed, test.Sprint("expected consumed to be false"))
+		test.SliceEmpty(t, result.Value, test.Sprint("expected result value to be empty"))
+		if t.Failed() {
+			t.FailNow()
+		}
+		return parseErr
+	}
+
 	t.Run("fails with wrong contents", rapid.MakeCheck(func(t *rapid.T) {
 		s := rapid.SliceOfN(rapid.Byte(), 1, -1).Draw(t, "s")
 		input := rapid.SliceOfN(rapid.Byte(), len(s), -1).
 			Filter(notP(hasPrefix(s))).Draw(t, "input")
-		start := gigaparsec.MakeState(cursor.NewSlice(input))
-
-		consumed, result, err := gigaparsec.Slice(s)(start)
-		test.ErrorAs(t, err, &gigaparsec.ParseError{})
-		test.False(t, consumed, test.Sprint("expected consumed to be false"))
-		test.SliceEmpty(t, result.Value)
+		assertParseFails(t, input, gigaparsec.Slice(s))
 	}))
 	t.Run("fails at end of input", rapid.MakeCheck(func(t *rapid.T) {
 		s := rapid.SliceOfN(rapid.Byte(), 1, -1).Draw(t, "s")
 		inputLen := rapid.IntRange(0, len(s)-1).Draw(t, "inputLen")
 		input := s[:inputLen]
-		start := gigaparsec.MakeState(cursor.NewSlice(input))
-
-		consumed, result, err := gigaparsec.Slice(s)(start)
-		test.ErrorAs(t, err, &gigaparsec.ParseError{})
-		test.False(t, consumed, test.Sprint("expected consumed to be false"))
-		test.SliceEmpty(t, result.Value)
+		assertParseFails(t, input, gigaparsec.Slice(s))
 	}))
 	t.Run("fails when read fails", Todo)
 	t.Run("succeeds when contents match", rapid.MakeCheck(func(t *rapid.T) {