test coverage for internal/accept

1 files changed, 81 insertions, 0 deletions

diff --git a/internal/accept/accept_test.go b/internal/accept/accept_test.go
new file mode 100644
index 0000000..90b6934
--- /dev/null
+++ b/internal/accept/accept_test.go
@@ -0,0 +1,81 @@
+// SPDX-FileCopyrightText: 2026 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package accept_test
+
+import (
+	"testing"
+
+	"go.xyrillian.de/gg/assert"
+	"go.xyrillian.de/gg/internal/accept"
+	. "go.xyrillian.de/gg/option"
+)
+
+func TestAcceptWithHeader(t *testing.T) {
+	h := accept.ParseHeader([]string{"text/*;q=0.3, text/plain;format=flowed, text/plain;format=fixed;q=0.4, */*;q=0.5"})
+
+	assert.Equal(t, h.Negotiate(
+		"image/png",                // matches with q=0.5
+		"text/plain; format=fixed", // matches with q=0.4
+	), Some("image/png"))
+
+	assert.Equal(t, h.Negotiate(
+		"image/png",                 // matches with q=0.5
+		"text/plain; format=flowed", // matches with q=1.0
+	), Some("text/plain; format=flowed"))
+
+	assert.Equal(t, h.Negotiate(
+		"text/plain",                // matches with q=0.7
+		"text/plain; format=flowed", // matches with q=1.0
+	), Some("text/plain; format=flowed"))
+
+	assert.Equal(t, h.Negotiate(
+		"text/plain",               // matches with q=0.7
+		"text/plain; format=other", // matches with q=0.3
+	), Some("text/plain"))
+
+	assert.Equal(t, h.Negotiate(
+		"text/markdown", // matches with q=0.3
+		"text/plain",    // matches with q=0.3 (but first wins)
+	), Some("text/markdown"))
+}
+
+func TestAcceptWithoutHeader(t *testing.T) {
+	// Negotiate() will always pick the first option
+	h := accept.ParseHeader(nil)
+
+	assert.Equal(t, h.Negotiate(
+		"image/png",
+		"image/jpeg",
+	), Some("image/png"))
+
+	assert.Equal(t, h.Negotiate(nil...), None[string]())
+
+	// malformed media types are ignored
+	assert.Equal(t, h.Negotiate(
+		"image/png/foo",
+		"image/jpeg",
+	), Some("image/jpeg"))
+
+	assert.Equal(t, h.Negotiate(
+		"image/png/foo",
+		"image/jpeg/foo",
+	), None[string]())
+}
+
+func TestAcceptWithMalformedHeader(t *testing.T) {
+	for _, brokenHeader := range []string{
+		"text/plain, text/markdown/foo",  // malformed media type
+		"text/plain, image/png; q=high",  // malformed q-value
+		"text/plain, image/jpeg; q=1.25", // q-value out of range
+	} {
+		h := accept.ParseHeader([]string{brokenHeader})
+
+		// broken headers are ignored completely, so the first option wins by default
+		assert.Equal(t, h.Negotiate(
+			"image/png",
+			"image/jpeg",
+			"text/plain",
+		), Some("image/png"))
+	}
+}