Add snapshot tests

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