3 files changed, 162 insertions, 2 deletions
diff --git a/src/SMAPI.Tests/Utilities/KeybindListTests.cs b/src/SMAPI.Tests/Utilities/KeybindListTests.cs
new file mode 100644
index 00000000..0bd6ec17
--- /dev/null
+++ b/src/SMAPI.Tests/Utilities/KeybindListTests.cs
@@ -0,0 +1,152 @@
+using System;
+using System.Collections.Generic;
+using NUnit.Framework;
+using StardewModdingAPI;
+using StardewModdingAPI.Utilities;
+
+namespace SMAPI.Tests.Utilities
+{
+    /// <summary>Unit tests for <see cref="KeybindList"/>.</summary>
+    [TestFixture]
+    internal class KeybindListTests
+    {
+        /*********
+        ** Unit tests
+        *********/
+        /****
+        ** TryParse
+        ****/
+        /// <summary>Assert the parsed fields when constructed from a simple single-key string.</summary>
+        [TestCaseSource(nameof(KeybindListTests.GetAllButtons))]
+        public void TryParse_SimpleValue(SButton button)
+        {
+            // act
+            bool success = KeybindList.TryParse($"{button}", out KeybindList parsed, out string[] errors);
+
+            // assert
+            Assert.IsTrue(success, "Parsing unexpectedly failed.");
+            Assert.IsNotNull(parsed, "The parsed result should not be null.");
+            Assert.AreEqual(parsed.ToString(), $"{button}");
+            Assert.IsNotNull(errors, message: "The errors should never be null.");
+            Assert.IsEmpty(errors, message: "The input bindings incorrectly reported errors.");
+        }
+
+        /// <summary>Assert the parsed fields when constructed from multi-key values.</summary>
+        [TestCase("", ExpectedResult = "None")]
+        [TestCase("    ", ExpectedResult = "None")]
+        [TestCase(null, ExpectedResult = "None")]
+        [TestCase("A + B", ExpectedResult = "A + B")]
+        [TestCase("A+B", ExpectedResult = "A + B")]
+        [TestCase("      A+     B    ", ExpectedResult = "A + B")]
+        [TestCase("a +b", ExpectedResult = "A + B")]
+        [TestCase("a +b, LEFTcontrol + leftALT + LeftSHifT + delete", ExpectedResult = "A + B, LeftControl + LeftAlt + LeftShift + Delete")]
+
+        [TestCase(",", ExpectedResult = "None")]
+        [TestCase("A,", ExpectedResult = "A")]
+        [TestCase(",A", ExpectedResult = "A")]
+        public string TryParse_MultiValues(string input)
+        {
+            // act
+            bool success = KeybindList.TryParse(input, out KeybindList parsed, out string[] errors);
+
+            // assert
+            Assert.IsTrue(success, "Parsing unexpectedly failed.");
+            Assert.IsNotNull(parsed, "The parsed result should not be null.");
+            Assert.IsNotNull(errors, message: "The errors should never be null.");
+            Assert.IsEmpty(errors, message: "The input bindings incorrectly reported errors.");
+            return parsed.ToString();
+        }
+
+        /// <summary>Assert invalid values are rejected.</summary>
+        [TestCase("+", "Invalid empty button value")]
+        [TestCase("A+", "Invalid empty button value")]
+        [TestCase("+C", "Invalid empty button value")]
+        [TestCase("A + B +, C", "Invalid empty button value")]
+        [TestCase("A, TotallyInvalid", "Invalid button value 'TotallyInvalid'")]
+        [TestCase("A + TotallyInvalid", "Invalid button value 'TotallyInvalid'")]
+        public void TryParse_InvalidValues(string input, string expectedError)
+        {
+            // act
+            bool success = KeybindList.TryParse(input, out KeybindList parsed, out string[] errors);
+
+            // assert
+            Assert.IsFalse(success, "Parsing unexpectedly succeeded.");
+            Assert.IsNull(parsed, "The parsed result should be null.");
+            Assert.IsNotNull(errors, message: "The errors should never be null.");
+            Assert.AreEqual(expectedError, string.Join("; ", errors), "The errors don't match the expected ones.");
+        }
+
+
+        /****
+        ** GetState
+        ****/
+        /// <summary>Assert that <see cref="KeybindList.GetState"/> returns the expected result for a given input state.</summary>
+        // single value
+        [TestCase("A", "A:Held", ExpectedResult = SButtonState.Held)]
+        [TestCase("A", "A:Pressed", ExpectedResult = SButtonState.Pressed)]
+        [TestCase("A", "A:Released", ExpectedResult = SButtonState.Released)]
+        [TestCase("A", "A:None", ExpectedResult = SButtonState.None)]
+
+        // multiple values
+        [TestCase("A + B + C, D", "A:Released, B:None, C:None, D:Pressed", ExpectedResult = SButtonState.Pressed)] // right pressed => pressed
+        [TestCase("A + B + C, D", "A:Pressed, B:Held, C:Pressed, D:None", ExpectedResult = SButtonState.Pressed)] // left pressed => pressed
+        [TestCase("A + B + C, D", "A:Pressed, B:Pressed, C:Released, D:None", ExpectedResult = SButtonState.None)] // one key released but other keys weren't down last tick => none
+        [TestCase("A + B + C, D", "A:Held, B:Held, C:Released, D:None", ExpectedResult = SButtonState.Released)] // all three keys were down last tick and now one is released => released
+
+        // transitive
+        [TestCase("A, B", "A: Released, B: Pressed", ExpectedResult = SButtonState.Held)]
+        public SButtonState GetState(string input, string stateMap)
+        {
+            // act
+            bool success = KeybindList.TryParse(input, out KeybindList parsed, out string[] errors);
+            if (success && parsed?.Keybinds != null)
+            {
+                foreach (var keybind in parsed.Keybinds)
+#pragma warning disable 618 // method is marked obsolete because it should only be used in unit tests
+                    keybind.GetButtonState = key => this.GetStateFromMap(key, stateMap);
+#pragma warning restore 618
+            }
+
+            // assert
+            Assert.IsTrue(success, "Parsing unexpected failed");
+            Assert.IsNotNull(parsed, "The parsed result should not be null.");
+            Assert.IsNotNull(errors, message: "The errors should never be null.");
+            Assert.IsEmpty(errors, message: "The input bindings incorrectly reported errors.");
+            return parsed.GetState();
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get all defined buttons.</summary>
+        private static IEnumerable<SButton> GetAllButtons()
+        {
+            foreach (SButton button in Enum.GetValues(typeof(SButton)))
+                yield return button;
+        }
+
+        /// <summary>Get the button state defined by a mapping string.</summary>
+        /// <param name="button">The button to check.</param>
+        /// <param name="stateMap">The state map.</param>
+        private SButtonState GetStateFromMap(SButton button, string stateMap)
+        {
+            foreach (string rawPair in stateMap.Split(','))
+            {
+                // parse values
+                string[] parts = rawPair.Split(new[] { ':' }, 2);
+                if (!Enum.TryParse(parts[0], ignoreCase: true, out SButton curButton))
+                    Assert.Fail($"The state map is invalid: unknown button value '{parts[0].Trim()}'");
+                if (!Enum.TryParse(parts[1], ignoreCase: true, out SButtonState state))
+                    Assert.Fail($"The state map is invalid: unknown state value '{parts[1].Trim()}'");
+
+                // get state
+                if (curButton == button)
+                    return state;
+            }
+
+            Assert.Fail($"The state map doesn't define button value '{button}'.");
+            return SButtonState.None;
+        }
+    }
+}
diff --git a/src/SMAPI/Utilities/Keybind.cs b/src/SMAPI/Utilities/Keybind.cs
index 9d6cd6ee..dd8d2861 100644
--- a/src/SMAPI/Utilities/Keybind.cs
+++ b/src/SMAPI/Utilities/Keybind.cs
@@ -10,6 +10,14 @@ namespace StardewModdingAPI.Utilities
     public class Keybind
     {
         /*********
+        ** Fields
+        *********/
+        /// <summary>Get the current input state for a button.</summary>
+        [Obsolete("This property should only be used for unit tests.")]
+        internal Func<SButton, SButtonState> GetButtonState { get; set; } = SGame.GetInputState;
+
+
+        /*********
         ** Accessors
         *********/
         /// <summary>The buttons that must be down to activate the keybind.</summary>
@@ -97,7 +105,7 @@ namespace StardewModdingAPI.Utilities
         /// <summary>Get the keybind state relative to the previous tick.</summary>
         public SButtonState GetState()
         {
-            SButtonState[] states = this.Buttons.Select(SGame.GetInputState).Distinct().ToArray();
+            SButtonState[] states = this.Buttons.Select(this.GetButtonState).Distinct().ToArray();
 
             // single state
             if (states.Length == 1)
diff --git a/src/SMAPI/Utilities/KeybindList.cs b/src/SMAPI/Utilities/KeybindList.cs
index 4ae66ab7..1845285a 100644
--- a/src/SMAPI/Utilities/KeybindList.cs
+++ b/src/SMAPI/Utilities/KeybindList.cs
@@ -72,7 +72,7 @@ namespace StardewModdingAPI.Utilities
             if (rawErrors.Any())
             {
                 parsed = null;
-                errors = rawErrors.ToArray();
+                errors = rawErrors.Distinct().ToArray();
                 return false;
             }
             else