Save HTML snapshots with .html extension. (#447)

This is a small thing I noticed while browsing the code. If you save the snapshots with the `html` extension then you can make it easy to see preview the actual html in a browser locally.

* Save HTML snapshots with .html extension.

* Apply suggestions from code review

Co-authored-by: Max Desiatov <max@desiatov.com>

Tests/TokamakStaticHTMLTests/HTMLStrategy.swift

@@ -0,0 +1,22 @@
+// Copyright 2021 Tokamak contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#if canImport(SnapshotTesting)
+import SnapshotTesting
+
+extension Snapshotting where Value == String, Format == String {
+  public static let html = Snapshotting(pathExtension: "html", diffing: .lines)
+}
+
+#endif

Tests/TokamakStaticHTMLTests/HTMLTests.swift

@@ -44,7 +44,7 @@ final class HTMLTests: XCTestCase {
     let resultingHTML = StaticHTMLRenderer(OptionalBody(model: Model(color: Color.red)))
       .render(shouldSortAttributes: true)
 
-    assertSnapshot(matching: resultingHTML, as: .lines)
+    assertSnapshot(matching: resultingHTML, as: .html)
   }
 
   func testPaddingFusion() {
@@ -52,13 +52,13 @@ final class HTMLTests: XCTestCase {
       Color.red.padding(10).padding(20)
     ).render(shouldSortAttributes: true)
 
-    assertSnapshot(matching: nestedTwice, as: .lines)
+    assertSnapshot(matching: nestedTwice, as: .html)
 
     let nestedThrice = StaticHTMLRenderer(
       Color.red.padding(20).padding(20).padding(20)
     ).render(shouldSortAttributes: true)
 
-    assertSnapshot(matching: nestedThrice, as: .lines)
+    assertSnapshot(matching: nestedThrice, as: .html)
   }
 
   func testFontStacks() {
@@ -67,7 +67,7 @@ final class HTMLTests: XCTestCase {
         .font(.custom("Marker Felt", size: 17))
     ).render(shouldSortAttributes: true)
 
-    assertSnapshot(matching: customFont, as: .lines)
+    assertSnapshot(matching: customFont, as: .html)
 
     let fallbackFont = StaticHTMLRenderer(
       VStack {
@@ -77,7 +77,7 @@ final class HTMLTests: XCTestCase {
       .font(.system(.body, design: .serif))
     ).render(shouldSortAttributes: true)
 
-    assertSnapshot(matching: fallbackFont, as: .lines)
+    assertSnapshot(matching: fallbackFont, as: .html)
   }
 
   func testHTMLSanitizer() {
@@ -85,12 +85,12 @@ final class HTMLTests: XCTestCase {
 
     let sanitizedHTML = StaticHTMLRenderer(Text(text))
       .render(shouldSortAttributes: true)
-    assertSnapshot(matching: sanitizedHTML, as: .lines)
+    assertSnapshot(matching: sanitizedHTML, as: .html)
 
     let insecureHTML =
       StaticHTMLRenderer(Text(text)._domTextSanitizer(Sanitizers.HTML.insecure))
         .render(shouldSortAttributes: true)
-    assertSnapshot(matching: insecureHTML, as: .lines)
+    assertSnapshot(matching: insecureHTML, as: .html)
   }
 }