Add tests for CLI diff coloring

Author: fredemmott

.gitignore

@@ -1,4 +1,5 @@
 vendor/
+tests/examples/*.out
 *.swp
 *.swo
 .DS_Store

tests/StringDiffTest.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Vec};
+use namespace HH\Lib\{C, Str, Vec};
 use function Facebook\FBExpect\expect;
 
 /** Test string-specific functionality */
@@ -67,4 +67,30 @@ public function testUnifiedDiff(string $name): void {
       $name,
     );
   }
+
+  <<DataProvider('provideExamples')>>
+  public function testCLIColoredDiff(string $name): void {
+    $base = __DIR__.'/examples/'.$name;
+    $a = \file_get_contents($base.'.a');
+    $b = \file_get_contents($base.'.b');
+    $diff = CLIColoredUnifiedDiff::create($a, $b);
+
+    \file_put_contents($base.'.clidiff.out', $diff);
+
+    if (!\file_exists($base.'.clidiff.expect')) {
+      self::markTestIncomplete(Str\format(
+        "No expect file present; maybe:\n  cp %s.clidiff.out %s.clidiff.expect",
+        $base,
+        $base,
+      ));
+    }
+
+    expect($diff)->toBeSame(
+      \file_get_contents($base.'.clidiff.expect'),
+      'Did not match expected contents (- %s.clidiff.expect, +%s.clidiff.out)',
+      $name,
+      $name,
+      $name,
+    );
+  }
 }

tests/examples/delete_mid.clidiff.expect

@@ -0,0 +1,4 @@
+@@ -1,3 +1,2 @@
+ foo
+-bar
+ baz

tests/examples/insert_mid.clidiff.expect

@@ -0,0 +1,4 @@
+@@ -1,2 +1,3 @@
+ foo
++bar
+ baz

tests/examples/lots_of_context_replace.clidiff.expect

@@ -0,0 +1,9 @@
+@@ -8,7 +8,7 @@
+ 8
+ 9
+ 0
+-foo bat baz
++foo bar baz
+ 1
+ 2
+ 3

tests/examples/one_line_to_two.clidiff.expect

@@ -0,0 +1,4 @@
+@@ -1 +1,2 @@
+-Foo
++Bar
++Baz

tests/examples/replace_last.clidiff.expect

@@ -0,0 +1,5 @@
+@@ -1,3 +1,3 @@
+ foo
+ bar
+-baz
++herp

tests/examples/replace_multi.clidiff.expect

@@ -0,0 +1,6 @@
+@@ -1,3 +1,3 @@
+ foo
+-bar
+-baz
++herp
++derp

tests/examples/replace_word.clidiff.expect

@@ -0,0 +1,3 @@
+@@ -1 +1 @@
+-Framework
++Facebook

tests/examples/two_lines_to_one.clidiff.expect

@@ -0,0 +1,4 @@
+@@ -1,2 +1 @@
+-Foo
+-Bar
++Baz