mathias
23fa5427b7
One-line lede for list cards: collapses whitespace, prefers the first sentence within budget, else word-boundary truncation with an ellipsis. Pure and rune-based (multibyte-safe). Table-driven tests cover empty, short, first-sentence, word-boundary, and multibyte cases.
105 lines
2.4 KiB
Go
105 lines
2.4 KiB
Go
package web
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import "testing"
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func TestPreviewText(t *testing.T) {
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t.Parallel()
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tests := []struct {
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name string
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in string
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max int
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want string
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}{
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{
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name: "empty input",
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in: "",
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max: 160,
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want: "",
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},
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{
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name: "whitespace-only input",
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in: " \n\t ",
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max: 160,
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want: "",
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},
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{
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name: "short string unchanged",
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in: "A tidy little summary",
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max: 160,
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want: "A tidy little summary",
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},
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{
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name: "short single sentence unchanged",
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in: "Hello there.",
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max: 160,
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want: "Hello there.",
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},
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{
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name: "first sentence taken when more follows",
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in: "First sentence. Second sentence that we drop.",
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max: 160,
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want: "First sentence.",
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},
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{
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name: "first sentence with question mark",
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in: "What is this? It is a preview.",
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max: 160,
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want: "What is this?",
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},
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{
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name: "long string truncated on word boundary with ellipsis",
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// 5 ten-char words past the limit; max cuts mid "ones".
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in: "alpha bravo charlie delta echo foxtrot golf hotel india juliet",
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max: 30,
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// runes[:30] = "alpha bravo charlie delta echo"; ends exactly on a
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// word so the next char would be a space — backs off to last space.
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want: "alpha bravo charlie delta…",
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},
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{
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name: "no mid-word cut",
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in: "internationalization frameworks everywhere today",
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max: 25,
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// runes[:25] = "internationalization fram" — back off to the space
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// after the first word; never emit a partial word.
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want: "internationalization…",
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},
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{
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name: "multibyte safe truncation",
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// Accented + emoji runes; cutting on rune indices must not split a
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// multibyte sequence.
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in: "café déjà vû señor naïve résumé piñata fiancé",
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max: 20,
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want: "café déjà vû señor…",
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},
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{
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name: "multibyte short unchanged",
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in: "café señor",
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max: 160,
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want: "café señor",
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},
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{
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name: "collapses internal whitespace",
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in: "line one\n\n line two\tline three",
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max: 160,
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want: "line one line two line three",
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},
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{
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name: "sentence beyond max falls back to char truncation",
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in: "alpha bravo charlie delta echo foxtrot golf. short.",
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max: 20,
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want: "alpha bravo charlie…",
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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t.Parallel()
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got := previewText(tt.in, tt.max)
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if got != tt.want {
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t.Errorf("previewText(%q, %d) = %q, want %q", tt.in, tt.max, got, tt.want)
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}
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})
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}
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}
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