C#: Add test cases for raw string literals.

Author: michaelnebel

csharp/ql/test/library-tests/csharp11/Strings.cs

@@ -11,4 +11,28 @@ public string M1(int x)
             _ => "something else"
         }}.";
     }
+
+    public void M2()
+    {
+        // Raw string literal.
+        var message1 = """
+        This is my very long
+            text message that spans
+          accross multiple lines
+        and is very useful.
+        """;
+
+        // String interpolation using a raw string literal.
+        var message2 = $"""
+        The nested message
+          is "{message1}" and everything
+        spans multiple lines.
+        """;
+
+        // String interpolation using a raw string literal that requires double curly braces.
+        var message3 = $$"""
+        Show no curly braces: {{message1}}
+        Show matching set of curly braces: {{{message2}}}
+        """;
+    }
 }

csharp/ql/test/library-tests/csharp11/strings.expected

@@ -1,3 +1,19 @@
+interpolatedstrings
 | Strings.cs:8:16:12:12 | $"..." | Strings.cs:8:18:8:32 | "This is my int " |
 | Strings.cs:8:16:12:12 | $"..." | Strings.cs:8:34:12:9 | ... switch { ... } |
 | Strings.cs:8:16:12:12 | $"..." | Strings.cs:12:11:12:11 | "." |
+| Strings.cs:26:24:30:11 | $"..." | Strings.cs:27:1:28:14 | "The nested message\n  is \\"" |
+| Strings.cs:26:24:30:11 | $"..." | Strings.cs:28:16:28:23 | access to local variable message1 |
+| Strings.cs:26:24:30:11 | $"..." | Strings.cs:28:25:29:29 | "\\" and everything\nspans multiple lines." |
+| Strings.cs:33:24:36:11 | $"..." | Strings.cs:34:1:34:30 | "Show no curly braces: " |
+| Strings.cs:33:24:36:11 | $"..." | Strings.cs:34:33:34:40 | access to local variable message1 |
+| Strings.cs:33:24:36:11 | $"..." | Strings.cs:34:43:35:44 | "\nShow matching set of curly braces: {" |
+| Strings.cs:33:24:36:11 | $"..." | Strings.cs:35:47:35:54 | access to local variable message2 |
+| Strings.cs:33:24:36:11 | $"..." | Strings.cs:35:57:35:57 | "}" |
+stringliterals
+| Strings.cs:18:24:23:11 | "This is my very long\n    text message that spans\n  accross multiple lines\nand is very useful." |
+| Strings.cs:27:1:28:14 | "The nested message\n  is \\"" |
+| Strings.cs:28:25:29:29 | "\\" and everything\nspans multiple lines." |
+| Strings.cs:34:1:34:30 | "Show no curly braces: " |
+| Strings.cs:34:43:35:44 | "\nShow matching set of curly braces: {" |
+| Strings.cs:35:57:35:57 | "}" |

csharp/ql/test/library-tests/csharp11/strings.ql

@@ -4,3 +4,7 @@ query predicate interpolatedstrings(InterpolatedStringExpr se, Expr e) {
   se.getFile().getStem() = "Strings" and
   (e = se.getAText() or e = se.getAnInsert())
 }
+
+query predicate stringliterals(StringLiteral s) {
+  s.getFile().getStem() = "Strings" and s.getEnclosingCallable().getName() = "M2"
+}