Improve tests and add famous examples

diffless/languages/json/tests/json.ts

@@ -1,13 +1,9 @@
-import { readTextFile } from '../../../cli';
-import { Document } from '../../../model';
-import { announceHtml, fixture } from '../../../tests/test-util';
+import { announceHtml, fixtureDocument } from '../../../tests/test-util';
 import { jsonDiff, jsonLexicalDiff } from '../index';
 
 describe('JSON support', () => {
-    const mapReorderleftPath = fixture('single_map_reorder/before.json');
-    const mapReorderRightPath = fixture('single_map_reorder/after.json');
-    const mapReorderleft = new Document('file://' + mapReorderleftPath, readTextFile(mapReorderleftPath));
-    const mapReorderRight = new Document('file://' + mapReorderRightPath, readTextFile(mapReorderRightPath));
+    const mapReorderleft = fixtureDocument('single_map_reorder/before.json');
+    const mapReorderRight = fixtureDocument('single_map_reorder/after.json');
 
     describe('jsonLexicalDiff', () => {
         it('should match snapshot', () => {
@@ -27,10 +23,8 @@ describe('JSON support', () => {
         });
 
         it('should match snapshot', () => {
-            const leftPath = fixture('textual_changes/before.json');
-            const rightPath = fixture('textual_changes/after.json');
-            const left = new Document('file://' + leftPath, readTextFile(leftPath));
-            const right = new Document('file://' + rightPath, readTextFile(rightPath));
+            const left = fixtureDocument('textual_changes/before.json');
+            const right = fixtureDocument('textual_changes/after.json');
 
             const diff = jsonDiff(left, right);
 

diffless/languages/json/tests/lexer.ts

@@ -1,21 +1,15 @@
-import { readTextFile } from '../../../cli';
-import { Document } from '../../../model';
-import { fixture } from '../../../tests/test-util';
+import { fixtureDocument } from '../../../tests/test-util';
 import { tokenize } from '../lexer';
 
 describe('lexer', () => {
     describe('tokenize', () => {
         it('should match snapshot', () => {
-            const path = fixture('textual_changes/before.json');
-            const document = new Document('file://' + path, readTextFile(path));
-
+            const document = fixtureDocument('textual_changes/before.json');
             expect(tokenize(document)).toMatchSnapshot();
         });
 
         it('should match snapshot', () => {
-            const path = fixture('textual_changes/after.json');
-            const document = new Document('file://' + path, readTextFile(path));
-
+            const document = fixtureDocument('textual_changes/after.json');
             expect(tokenize(document)).toMatchSnapshot();
         });
     });

diffless/tests/__snapshots__/diffless.ts.snap

@@ -265,6 +265,41 @@ Array [
 ]
 `;
 
+exports[`array/diff lineDiff should be able to compare strings directly 2`] = `
+Array [
+  Object {
+    "left": Location {
+      "range": [4:1; 7:1),
+      "uri": "string:left",
+    },
+    "level": "Textual",
+    "right": Location {
+      "range": [4:1; 7:1),
+      "uri": "string:right",
+    },
+    "type": "Move",
+  },
+  Object {
+    "left": Location {
+      "range": [7:1; 10:1),
+      "uri": "string:left",
+    },
+    "level": "Textual",
+    "right": undefined,
+    "type": "Delete",
+  },
+  Object {
+    "left": undefined,
+    "level": "Textual",
+    "right": Location {
+      "range": [1:1; 4:1),
+      "uri": "string:right",
+    },
+    "type": "Add",
+  },
+]
+`;
+
 exports[`array/diff lineDiff should be possible to use no weight 1`] = `
 Array [
   Object {
@@ -298,3 +333,17 @@ Array [
   },
 ]
 `;
+
+exports[`array/diff lineDiff should produce good quality diff 1`] = `
+Array [
+  Object {
+    "left": undefined,
+    "level": "Textual",
+    "right": Location {
+      "range": [3:1; 7:1),
+      "uri": "file://diffless/tests/fixtures/patience/after.c",
+    },
+    "type": "Add",
+  },
+]
+`;

diffless/tests/diffless.ts

@@ -1,7 +1,7 @@
 import { ArrayDiffTool } from '../array/diff';
 import { characterDiff, lineDiff } from '../index';
 import { DiffLevel, Document } from '../model';
-import { announceHtml } from '../tests/test-util';
+import { announceHtml, fixtureDocument } from '../tests/test-util';
 import { stripMargin } from '../util';
 
 describe('array/diff', () => {
@@ -75,24 +75,35 @@ describe('array/diff', () => {
     });
 
     describe('lineDiff', () => {
-        const left = new Document('string:left', stripMargin
-            `abc
-            |def
-            |ghijklmn`,
-        );
-        const right = new Document('string:right', stripMargin
-            `abc
-            |ghijklmn
-            |def`,
-        );
-
         it('should consider line weight', () => {
+            const left = new Document('string:left', stripMargin
+                `abc
+                |def
+                |ghijklmn`,
+            );
+            const right = new Document('string:right', stripMargin
+                `abc
+                |ghijklmn
+                |def`,
+            );
+
             const diff = lineDiff(left, right);
             expect(diff.edits).toMatchSnapshot();
             announceHtml(left, right, diff.edits, 'move_lines_weighed');
         });
 
         it('should be possible to use no weight', () => {
+            const left = new Document('string:left', stripMargin
+                `abc
+                |def
+                |ghijklmn`,
+            );
+            const right = new Document('string:right', stripMargin
+                `abc
+                |ghijklmn
+                |def`,
+            );
+
             const tool = new ArrayDiffTool({
                 level: DiffLevel.Textual,
                 similarityThreshold: 0,
@@ -106,27 +117,70 @@ describe('array/diff', () => {
 
         it('should be able to compare strings directly', () => {
             const otherLeft = stripMargin
-            `"m"
-            |"z"
-            |"j"
-            |"a"
-            |"w"
-            |"x"
-            |"u"`;
+                `"m"
+                |"z"
+                |"j"
+                |"a"
+                |"w"
+                |"x"
+                |"u"`;
 
             const otherRight = stripMargin
-            `"a"
-            |"j"
-            |"m"
-            |"u"
-            |"w"
-            |"x"
-            |"z"`;
+                `"a"
+                |"j"
+                |"m"
+                |"u"
+                |"w"
+                |"x"
+                |"z"`;
 
             const diff = lineDiff(otherLeft, otherRight);
 
             expect(diff.edits).toMatchSnapshot();
             announceHtml(diff.left, diff.right, diff.edits, 'strings');
         });
+
+        it('should be able to compare strings directly', () => {
+            // from: https://news.ycombinator.com/item?id=13987217
+            const otherLeft = stripMargin
+                `a
+                |b
+                |c
+                |1
+                |2
+                |3
+                |x
+                |y
+                |z
+                |`;
+
+            const otherRight = stripMargin
+                `x
+                |y
+                |z
+                |1
+                |2
+                |3
+                |a
+                |b
+                |c
+                |`;
+
+            const diff = lineDiff(otherLeft, otherRight);
+
+            expect(diff.edits).toMatchSnapshot(); // FIXME result is wrong
+            announceHtml(diff.left, diff.right, diff.edits, 'move-fail');
+        });
+
+        it('should produce good quality diff', () => {
+            // from: https://bramcohen.livejournal.com/73318.html
+            const left = fixtureDocument('patience/before.c');
+            const right = fixtureDocument('patience/after.c');
+
+            const diff = lineDiff(left, right);
+
+            expect(diff.edits).toMatchSnapshot(); // FIXME result is poor
+            announceHtml(diff.left, diff.right, diff.edits, 'patience');
+        });
     });
 });

diffless/tests/fixtures/patience/after.c

@@ -0,0 +1,11 @@
+void func1() {
+    x += 1
+}
+
+void functhreehalves() {
+x += 1.5
+}
+
+void func2() {
+    x += 2
+}

diffless/tests/fixtures/patience/before.c

@@ -0,0 +1,7 @@
+void func1() {
+    x += 1
+}
+
+void func2() {
+    x += 2
+}

diffless/tests/test-util.ts

@@ -1,12 +1,17 @@
 import { resolve } from 'path';
 
-import { saveAnnotatedHtml } from '../cli';
+import { readTextFile, saveAnnotatedHtml } from '../cli';
 import { Document, Edit } from '../model';
 
 export function fixture(path: string) {
     return `diffless/tests/fixtures/${path}`;
 }
 
+export function fixtureDocument(path: string): Document {
+    path = fixture(path);
+    return new Document('file://' + path, readTextFile(path));
+}
+
 let seed = 0;
 export function announceHtml(left: Document, right: Document, edits: Edit[], name?: string) {
     const outputPath = `dist/tmp_${name || seed++}.html`;