add Attribute definition

Updates #2.

Assets/Scripts/Attribute.cs

@@ -0,0 +1,42 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public struct Attribute
+{
+    [SerializeField]
+    private long _base;
+
+    public Attribute(long stat)
+    {
+        _base = stat;
+    }
+
+    /// <summary>
+    /// Permanently increase the stat value.
+    /// </summary>
+    /// <param name="by">Increase amount.</param>
+    public void LevelUp(long by)
+    {
+        _base += by;
+    }
+
+    /// <summary>
+    /// Calculates the stat value with accumulated buff and debuff modifiers.
+    /// </summary>
+    /// <param name="baseBonus">Additive bonus applied before multiplicative scaling.</param>
+    /// <param name="permyriadBonus">Multiplicative scaling in hundredths of a percent. E.g., 625 permyriad corresponds to 6.25%.</param>
+    /// <param name="flatBonus">Additive bonus applied after multiplicative scaling.</param>
+    /// <returns>(base + baseBonus) * (100% + permyriadBonus) + flatBonus, bounded below by 0.</returns>
+    public long Calc(long baseBonus, long permyriadBonus, long flatBonus)
+    {
+        var r = _base + baseBonus;
+        var m = permyriadBonus + 10000;
+        r = r * (m / 10000) + (r / 10000) * (m % 10000) + flatBonus;
+        if (r <= 0)
+        {
+            return 0;
+        }
+        return r;
+    }
+}

Assets/Scripts/Attribute.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: b7d084c6ff925d3448dad326e9980f08
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/IdleSurvivors.asmdef

@@ -0,0 +1,3 @@
+{
+	"name": "IdleSurvivors"
+}

Assets/Scripts/IdleSurvivors.asmdef.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: e5250715ffed2b644bacb4c76ae6a775
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Tests.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 9048b33fed80c814dbfdb2713db19d6d
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Tests/AttributeTest.cs

@@ -0,0 +1,25 @@
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+
+public class AttributeTest
+{
+    [Test]
+    [TestCase(1000000, 0, 0, 0, 0, ExpectedResult = 1000000)]
+    [TestCase(1000000, 1, 0, 0, 0, ExpectedResult = 1000001)]
+    [TestCase(1000000, 0, 2, 0, 0, ExpectedResult = 1000002)]
+    [TestCase(1000000, 0, 0, 10000, 0, ExpectedResult = 2000000)]
+    [TestCase(1000000, 0, 0, 0, 3, ExpectedResult = 1000003)]
+    [TestCase(0, 1000000, 1000000, 5000, 1000, ExpectedResult = 3001000)]
+    [TestCase(1000000, 0, 0, -10000, 0, ExpectedResult = 0)]
+    [TestCase(1000000, 0, 0, -20000, 0, ExpectedResult = 0)]
+    [TestCase(1000000, 0, 0, -20000, 50, ExpectedResult = 0)]
+    public long Calc(long startStat, long levelUp, long baseBonus, long permyriadBonus, long flatBonus)
+    {
+        var attr = new Attribute(startStat);
+        attr.LevelUp(levelUp);
+        return attr.Calc(baseBonus, permyriadBonus, flatBonus);
+    }
+}

Assets/Tests/AttributeTest.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: d4d405f62d1e7dc4aaf451051bf27d73
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Tests/Tests.asmdef

@@ -0,0 +1,24 @@
+{
+    "name": "Tests",
+    "rootNamespace": "",
+    "references": [
+        "UnityEngine.TestRunner",
+        "UnityEditor.TestRunner",
+        "IdleSurvivors"
+    ],
+    "includePlatforms": [
+        "Editor"
+    ],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": true,
+    "precompiledReferences": [
+        "nunit.framework.dll"
+    ],
+    "autoReferenced": false,
+    "defineConstraints": [
+        "UNITY_INCLUDE_TESTS"
+    ],
+    "versionDefines": [],
+    "noEngineReferences": false
+}

Assets/Tests/Tests.asmdef.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 0e24b24d5798c7c4b979b314b1a7afce
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: