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// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
package diff
import (
"regexp"
"testing"
"github.com/google/go-cmp/cmp"
"github.com/google/go-cmp/cmp/cmpopts"
)
var region_eq = cmpopts.EquateComparable(Region{})
func TestWordDiffCenter(t *testing.T) {
re := regexp.MustCompile(`\S+`)
type tc struct {
left, right string
left_regions []Region
right_regions []Region
}
tests := []tc{
{
// word count equal, single substitution at index 1 → positional pair
// "quick" vs "slow": no common chars → full words
left: "the quick brown fox", right: "the slow brown fox",
left_regions: []Region{{4, 5}},
right_regions: []Region{{4, 4}},
},
{
left: "hello world", right: "hello world",
left_regions: nil,
right_regions: nil,
},
{
// word count equal, single substitution at index 1 → positional pair
// "bar" vs "qux": no common chars → full words
left: "foo bar baz", right: "foo qux baz",
left_regions: []Region{{4, 3}},
right_regions: []Region{{4, 3}},
},
{
// left has 3 words, right has 4 → word counts differ with unmatched
// changed words → fall back to changed_center
// changed_center gives: offset=4 (common "aaa "), suffix="ccc"(4)
// left_size=3 ("bbb"), right_size=7 ("xxx yyy")
left: "aaa bbb ccc", right: "aaa xxx yyy ccc",
left_regions: []Region{{4, 3}},
right_regions: []Region{{4, 7}},
},
{
// word on left deleted: unmatched changed word → fall back to changed_center
// changed_center: prefix="aaa "(4), suffix=" ccc ddd"(8)
// left_size=3 ("bbb"), right_size=-1 → nil
left: "aaa bbb ccc ddd", right: "aaa ccc ddd",
left_regions: []Region{{4, 3}},
right_regions: nil,
},
{
// word counts equal, single substitution at index 3 → positional pair
// "fox" vs "cat": no common chars → full words
left: "the quick brown fox over the lazy dog", right: "the quick brown cat over the lazy dog",
left_regions: []Region{{16, 3}},
right_regions: []Region{{16, 3}},
},
{
// single word, positional pair with common char prefix "version" (7)
left: "version1",
right: "version2",
left_regions: []Region{{7, 1}},
right_regions: []Region{{7, 1}},
},
{
// positional pair at index 1, char prefix="prefix"(6), suffix="suffix"(6)
// word at offset 7 → highlight offset 13, size 2
left: "update prefixABsuffix done",
right: "update prefixCDsuffix done",
left_regions: []Region{{13, 2}},
right_regions: []Region{{13, 2}},
},
{
// equal word count, multiple positional pairs (all words changed)
// each pair has no common chars → full-word regions
left: "aaa bbb ccc", right: "xxx yyy zzz",
left_regions: []Region{{0, 3}, {4, 3}, {8, 3}},
right_regions: []Region{{0, 3}, {4, 3}, {8, 3}},
},
{
// pure insertion on right side → unmatched changed word → fall back to changed_center
// changed_center finds common prefix "aaa bbb ccc" (11 bytes) and suffix "";
// left_size=0 (nil), right_size=4 (" ddd" inserted at the end)
left: "aaa bbb ccc", right: "aaa bbb ccc ddd",
left_regions: nil,
right_regions: []Region{{11, 4}},
},
}
for _, tc := range tests {
c := word_diff_center(tc.left, tc.right, re)
if diff := cmp.Diff(tc.left_regions, c.left_regions, region_eq); diff != "" {
t.Errorf("word_diff_center(%q, %q) left_regions mismatch: %s", tc.left, tc.right, diff)
}
if diff := cmp.Diff(tc.right_regions, c.right_regions, region_eq); diff != "" {
t.Errorf("word_diff_center(%q, %q) right_regions mismatch: %s", tc.left, tc.right, diff)
}
}
}
func TestChangedCenter(t *testing.T) {
type tc struct {
left, right string
left_regions []Region
right_regions []Region
}
tests := []tc{
{
left: "the quick brown fox", right: "the slow brown fox",
left_regions: []Region{{4, 5}},
right_regions: []Region{{4, 4}},
},
{
left: "hello world", right: "hello world",
left_regions: nil,
right_regions: nil,
},
}
for _, tc := range tests {
c := changed_center(tc.left, tc.right)
if diff := cmp.Diff(tc.left_regions, c.left_regions, region_eq); diff != "" {
t.Errorf("changed_center(%q, %q) left_regions mismatch: %s", tc.left, tc.right, diff)
}
if diff := cmp.Diff(tc.right_regions, c.right_regions, region_eq); diff != "" {
t.Errorf("changed_center(%q, %q) right_regions mismatch: %s", tc.left, tc.right, diff)
}
}
}
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