chore: import upstream snapshot with attribution

pkg/http/headers/parse_test.go

@@ -0,0 +1,58 @@
+package headers
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseCommaSeparated(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected []string
+	}{
+		{
+			name:     "empty string",
+			input:    "",
+			expected: []string{},
+		},
+		{
+			name:     "single value",
+			input:    "foo",
+			expected: []string{"foo"},
+		},
+		{
+			name:     "multiple values",
+			input:    "foo,bar,baz",
+			expected: []string{"foo", "bar", "baz"},
+		},
+		{
+			name:     "whitespace trimmed",
+			input:    " foo , bar , baz ",
+			expected: []string{"foo", "bar", "baz"},
+		},
+		{
+			name:     "empty values filtered",
+			input:    "foo,,bar,",
+			expected: []string{"foo", "bar"},
+		},
+		{
+			name:     "only commas",
+			input:    ",,,",
+			expected: []string{},
+		},
+		{
+			name:     "whitespace only values filtered",
+			input:    "foo,   ,bar",
+			expected: []string{"foo", "bar"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ParseCommaSeparated(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}