Add tests cases for failing multi line string

Author: kimdv

Tests/SwiftSyntaxBuilderTest/StringLiteralTests.swift

@@ -170,4 +170,137 @@ final class StringLiteralTests: XCTestCase {
       """#
     )
   }
+
+  func testMultiLineStringWithResultBuilder() {
+    let buildable = StringLiteralExprSyntax(
+      openQuote: .multilineStringQuoteToken(leadingTrivia: .newline, trailingTrivia: .newline),
+      segments: StringLiteralSegmentsSyntax {
+        StringSegmentSyntax(content: .stringSegment(#"Error validating child at index \(index) of \(nodeKind):"#), trailingTrivia: .newline)
+        StringSegmentSyntax(content: .stringSegment(#"Node did not satisfy any node choice requirement."#), trailingTrivia: .newline)
+        StringSegmentSyntax(content: .stringSegment(#"Validation failures:"#), trailingTrivia: .newline)
+        StringSegmentSyntax(content: .stringSegment(#"\(nonNilErrors.map({ "- \($0.description)" }).joined(separator: "\n"))"#))
+      },
+      closeQuote: .multilineStringQuoteToken(leadingTrivia: .newline, trailingTrivia: .newline)
+    )
+
+    AssertBuildResult(
+      buildable,
+      #"""
+      Error validating child at index \(index) of \(nodeKind):
+      Node did not satisfy any node choice requirement.
+      Validation failures:
+      \(nonNilErrors.map({ "- \($0.description)" }).joined(separator: "\n"))
+      """#
+    )
+  }
+
+  func testMultiLineStringWithFunctions() {
+    let buildable = StringLiteralExprSyntax(
+      openQuote: .multilineStringQuoteToken(trailingTrivia: .newline),
+      content:
+        #"""
+        assertionFailure("""
+          Error validating child at index \(index) of \(nodeKind):
+          Node did not satisfy any node choice requirement.
+          Validation failures:
+          \(nonNilErrors.map({ "- \($0.description)" }).joined(separator: "\n") )
+          """, file: file, line: line)
+        """#
+      ,
+      closeQuote: .multilineStringQuoteToken(leadingTrivia: .newline)
+    )
+
+    AssertBuildResult(
+      buildable,
+      ##"""
+      #"""
+      assertionFailure("""\#n  Error validating child at index \(index) of \(nodeKind):\#n  Node did not satisfy any node choice requirement.\#n  Validation failures:\#n  \(nonNilErrors.map({ "- \($0.description)" }).joined(separator: "\n") )\#n  """, file: file, line: line)
+      """#
+      """##
+
+    )
+  }
+
+  func testMultiStringLiteralInExpr() {
+    let buildable = ExprSyntax(
+      #"""
+      assertionFailure("""
+        Error validating child at index \(index) of \(nodeKind):
+        Node did not satisfy any node choice requirement.
+        Validation failures:
+        \(nonNilErrors.map({ "- \($0.description)" }).joined(separator: "\n") )
+        """, file: file, line: line)
+      """#
+    )
+
+    AssertBuildResult(
+      buildable,
+      #"""
+      assertionFailure("""
+            Error validating child at index \(index) of \(nodeKind):
+            Node did not satisfy any node choice requirement.
+            Validation failures:
+            \(nonNilErrors.map( { "- \($0.description)" }).joined(separator: "\n") )
+            """, file: file, line: line)
+      """#
+    )
+  }
+
+  func testMultiStringLiteralInIfExpr() {
+    let buildable = ExprSyntax(
+      #"""
+      if nonNilErrors.count == errors.count {
+        assertionFailure("""
+          Error validating child at index
+          Node did not satisfy any node choice requirement.
+          Validation failures:
+          """)
+      }
+      """#
+    )
+
+    AssertBuildResult(
+      buildable,
+      #"""
+      if nonNilErrors.count == errors.count {
+          assertionFailure("""
+                  Error validating child at index
+                  Node did not satisfy any node choice requirement.
+                  Validation failures:
+                  """)
+      }
+      """#
+    )
+  }
+
+  func testMultiStringLiteralOnNewlineInIfExpr() {
+    let buildable = ExprSyntax(
+      #"""
+      if true {
+        assertionFailure(
+          """
+          Error validating child at index
+          Node did not satisfy any node choice requirement.
+          Validation failures:
+          """
+        )
+      }
+      """#
+    )
+
+    AssertBuildResult(
+      buildable,
+      #"""
+      if true {
+          assertionFailure(
+              """
+                  Error validating child at index
+                  Node did not satisfy any node choice requirement.
+                  Validation failures:
+                  """
+          )
+      }
+      """#
+    )
+  }
 }