add token support for instance fields, expand unit test (#296)

src/StardewModdingAPI.Tests/TranslationTests.cs

@@ -180,7 +180,7 @@ namespace StardewModdingAPI.Tests
         ** Translation tokens
         ****/
         [Test(Description = "Assert that multiple translation tokens are replaced correctly regardless of the token structure.")]
-        public void Translation_Tokens([Values("anonymous object", "IDictionary<string, object>", "IDictionary<string, string>")] string structure)
+        public void Translation_Tokens([Values("anonymous object", "class", "IDictionary<string, object>", "IDictionary<string, string>")] string structure)
         {
             // arrange
             string start = Guid.NewGuid().ToString("N");
@@ -197,6 +197,10 @@ namespace StardewModdingAPI.Tests
                     translation = translation.Tokens(new { start, middle, end });
                     break;
 
+                case "class":
+                    translation = translation.Tokens(new TokenModel { Start = start, Middle = middle, End = end });
+                    break;
+
                 case "IDictionary<string, object>":
                     translation = translation.Tokens(new Dictionary<string, object> { ["start"] = start, ["middle"] = middle, ["end"] = end });
                     break;
@@ -323,5 +327,22 @@ namespace StardewModdingAPI.Tests
         {
             return string.Format(Translation.PlaceholderText, key);
         }
+
+
+        /*********
+        ** Test models
+        *********/
+        /// <summary>A model used to test token support.</summary>
+        private class TokenModel
+        {
+            /// <summary>A sample token property.</summary>
+            public string Start { get; set; }
+
+            /// <summary>A sample token property.</summary>
+            public string Middle { get; set; }
+
+            /// <summary>A sample token field.</summary>
+            public string End;
+        }
     }
 }

src/StardewModdingAPI/Translation.cs

@@ -107,8 +107,11 @@ namespace StardewModdingAPI
                 // from object properties
                 else
                 {
-                    foreach (PropertyInfo prop in tokens.GetType().GetProperties())
+                    Type type = tokens.GetType();
+                    foreach (PropertyInfo prop in type.GetProperties())
                         tokenLookup[prop.Name] = prop.GetValue(tokens)?.ToString();
+                    foreach (FieldInfo field in type.GetFields())
+                        tokenLookup[field.Name] = field.GetValue(tokens)?.ToString();
                 }
             }