Add snapshot tests

Package.resolved

@@ -0,0 +1,42 @@
+{
+  "originHash" : "f1d7267746a12d71d624c75daa345adf396e99a25ae07ee92716ae508085d85e",
+  "pins" : [
+    {
+      "identity" : "swift-custom-dump",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/pointfreeco/swift-custom-dump",
+      "state" : {
+        "revision" : "82645ec760917961cfa08c9c0c7104a57a0fa4b1",
+        "version" : "1.3.3"
+      }
+    },
+    {
+      "identity" : "swift-snapshot-testing",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/pointfreeco/swift-snapshot-testing",
+      "state" : {
+        "revision" : "a8b7c5e0ed33d8ab8887d1654d9b59f2cbad529b",
+        "version" : "1.18.7"
+      }
+    },
+    {
+      "identity" : "swift-syntax",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/swiftlang/swift-syntax",
+      "state" : {
+        "revision" : "4799286537280063c85a32f09884cfbca301b1a1",
+        "version" : "602.0.0"
+      }
+    },
+    {
+      "identity" : "xctest-dynamic-overlay",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/pointfreeco/xctest-dynamic-overlay",
+      "state" : {
+        "revision" : "34e463e98ab8541c604af706c99bed7160f5ec70",
+        "version" : "1.8.1"
+      }
+    }
+  ],
+  "version" : 3
+}

Package.swift

@@ -14,7 +14,9 @@ let package = Package(
   products: [
     .library(name: "SwiftUIMath", targets: ["SwiftUIMath"])
   ],
-  dependencies: [],
+  dependencies: [
+    .package(url: "https://github.com/pointfreeco/swift-snapshot-testing", from: "1.18.7")
+  ],
   targets: [
     .target(
       name: "SwiftUIMath",
@@ -23,7 +25,11 @@ let package = Package(
     ),
     .testTarget(
       name: "SwiftUIMathTests",
-      dependencies: ["SwiftUIMath"]
+      dependencies: [
+        "SwiftUIMath",
+        .product(name: "SnapshotTesting", package: "swift-snapshot-testing"),
+      ],
+      exclude: ["__Snapshots__"]
     ),
   ]
 )

Tests/SwiftUIMathTests/MathTests.swift

@@ -0,0 +1,96 @@
+#if os(iOS)
+  import SnapshotTesting
+  import SwiftUI
+  import Testing
+
+  @testable import SwiftUIMath
+
+  @MainActor
+  struct MathTests {
+    private let layout = SwiftUISnapshotLayout.device(config: .iPhone8)
+
+    @Test
+    func displayAndInlineStyles() {
+      let view = VStack(alignment: .leading, spacing: 16) {
+        Math("\\frac{1}{2}+\\sqrt{2}+\\sum_{i=1}^{n}x_i")
+          .mathTypesettingStyle(.display)
+          .mathFont(Math.Font(name: .latinModern, size: 24))
+
+        Math("\\int_0^1 x^2\\,dx = \\frac{1}{3}")
+          .mathTypesettingStyle(.text)
+          .mathFont(Math.Font(name: .libertinus, size: 20))
+      }
+      .background(Color.guide)
+      .padding(.horizontal)
+
+      assertSnapshot(of: view, as: .image(layout: layout))
+    }
+
+    @Test
+    func multicolorExpressions() {
+      let view = VStack(alignment: .leading, spacing: 16) {
+        Math("\\color{#cc0000}{a}+\\color{#00aa00}{b}+\\color{#0000cc}{c}")
+          .mathTypesettingStyle(.text)
+          .mathRenderingMode(.multicolor)
+          .mathFont(Math.Font(name: .latinModern, size: 22))
+
+        Math("\\textcolor{#ff8800}{\\int_0^1 x^2\\,dx}=\\textcolor{#0088ff}{\\frac{1}{3}}")
+          .mathRenderingMode(.multicolor)
+          .mathFont(Math.Font(name: .libertinus, size: 20))
+      }
+      .background(Color.guide)
+      .padding(.horizontal)
+
+      assertSnapshot(of: view, as: .image(layout: layout))
+    }
+
+    @Test
+    func matricesAndCases() {
+      let view = VStack(alignment: .leading, spacing: 16) {
+        Math("A=\\begin{pmatrix}1&2\\\\3&4\\end{pmatrix}")
+          .mathTypesettingStyle(.display)
+          .mathFont(Math.Font(name: .asana, size: 22))
+
+        Math("\\begin{cases} x + y = 5 \\\\ 2x - y = 1 \\end{cases}")
+          .mathTypesettingStyle(.display)
+          .mathFont(Math.Font(name: .termes, size: 22))
+      }
+      .background(Color.guide)
+      .padding(.horizontal)
+
+      assertSnapshot(of: view, as: .image(layout: layout))
+    }
+
+    @Test
+    func largeOperatorsAndLimits() {
+      let view = VStack(alignment: .leading, spacing: 16) {
+        Math("\\lim_{n\\to\\infty}\\sum_{k=1}^{n}\\frac{1}{k^2}=\\frac{\\pi^2}{6}")
+          .mathTypesettingStyle(.display)
+          .mathFont(Math.Font(name: .xits, size: 22))
+      }
+      .background(Color.guide)
+      .padding(.horizontal)
+
+      assertSnapshot(of: view, as: .image(layout: layout))
+    }
+
+    @Test
+    func inlineTextWrapping() {
+      let view = VStack(alignment: .leading, spacing: 16) {
+        Math("\\text{Rappelons la conversion : 1 km équivaut à 1000 m.}")
+          .mathTypesettingStyle(.text)
+          .mathFont(Math.Font(name: .latinModern, size: 18))
+      }
+      .background(Color.guide)
+      .padding(.horizontal)
+
+      assertSnapshot(of: view, as: .image(layout: layout))
+    }
+  }
+
+  extension Color {
+    fileprivate static var guide: Color {
+      .accentColor.opacity(0.06)
+    }
+  }
+#endif