[New Exercise]: Robot Name (#388)

Add exercise `Robot Name`

config.json

@@ -790,6 +790,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "robot-name",
+        "name": "Robot Name",
+        "uuid": "0b35919e-ccba-4f45-8a03-504869e229ae",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "simple-linked-list",
         "name": "Simple Linked List",

exercises/practice/robot-name/.docs/instructions.md

@@ -0,0 +1,14 @@
+# Instructions
+
+Manage robot factory settings.
+
+When a robot comes off the factory floor, it has no name.
+
+The first time you turn on a robot, a random name is generated in the format of two uppercase letters followed by three digits, such as RX837 or BC811.
+
+Every once in a while we need to reset a robot to its factory settings, which means that its name gets wiped.
+The next time you ask, that robot will respond with a new random name.
+
+The names must be random: they should not follow a predictable sequence.
+Using random names means a risk of collisions.
+Your solution must ensure that every existing robot has a unique name.

exercises/practice/robot-name/.meta/RobotName.example.ps1

@@ -0,0 +1,45 @@
+<#
+.SYNOPSIS
+    Manage robot factory settings.
+
+.DESCRIPTION
+    Generate a random name for a robot when it is created.
+    The name should be in the format of two uppercase letters followed by three digits, such as RX837 or BC811.
+    The robot should be able to reset and get a completely new name. (Old name that got reset should not be available for future use)
+
+.EXAMPLE
+    $robot = [Robot]::new()
+    $robot.Name
+    Returns: "EX341"
+#>
+
+Class Robot {
+    [String]$Name
+    static  $NameBank = [System.Collections.Generic.HashSet[string]]::new()
+
+    Robot() {
+        $this.Name = $this.GenerateName()
+    }
+
+    [string] GenerateName() {
+        do {
+            $newName = $this.GenerateNum() + $this.GenerateChars()
+        } while (
+            [Robot]::NameBank.Contains($newName)
+        )
+        [Robot]::NameBank.Add($newName)
+        return $newName
+    }
+
+    [string] GenerateNum() {
+        return -join ('A'..'Z' | Get-Random -Count 2)
+    }
+
+    [string] GenerateChars() {
+        return -join ('1'..'9' | Get-Random -Count 3) 
+    }
+
+    [void] Reset() {
+        $this.Name = $this.GenerateName()
+    }
+}

exercises/practice/robot-name/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "glaxxie"
+  ],
+  "files": {
+    "solution": [
+      "RobotName.ps1"
+    ],
+    "test": [
+      "RobotName.tests.ps1"
+    ],
+    "example": [
+      ".meta/RobotName.example.ps1"
+    ]
+  },
+  "blurb": "Manage robot factory settings.",
+  "source": "A debugging session with Paul Blackwell at gSchool."
+}

exercises/practice/robot-name/RobotName.ps1

@@ -0,0 +1,26 @@
+<#
+.SYNOPSIS
+    Manage robot factory settings.
+
+.DESCRIPTION
+    Generate a random name for a robot when it is created.
+    The name should be in the format of two uppercase letters followed by three digits, such as RX837 or BC811.
+    The robot should be able to reset and get a completely new name. (Old name that got reset should not be available for future use)
+
+.EXAMPLE
+    $robot = [Robot]::new()
+    $robot.Name
+    Returns: "EX341"
+#>
+
+Class Robot {
+    [String]$Name
+
+    Robot() {
+        Throw "Please implement this class"
+    }
+
+    [void] Reset() {
+        Throw "Please implement this function"
+    }
+}

exercises/practice/robot-name/RobotName.tests.ps1

@@ -0,0 +1,47 @@
+BeforeAll {
+    . "./RobotName.ps1"
+}
+
+Describe "RobotName test cases" {
+    BeforeEach {
+        $robot = [Robot]::new()
+    }
+
+    It "robot has a name" {
+        $robot.Name | Should -MatchExactly "^[A-Z]{2}\d{3}$"
+    }
+
+    It "name is the same each time" {
+        $robot.Name | Should -BeExactly $robot.Name
+    }
+
+    It "different robot has different name" {
+        $robot2 = [Robot]::new()
+        $robot2.Name | Should -Not -Be $robot.Name
+    }
+
+    It "name can be reset" {
+        $initialName = $robot.Name
+        $robot.Reset()
+
+        $robot.Name | Should -Not -Be $initialName 
+    }
+
+    It "name is valid after many reset" {
+        for ($i = 0; $i -lt 100; $i++) {
+            $initialName = $robot.Name
+            $robot.Reset()
+            $robot.Name | Should -MatchExactly "^[A-Z]{2}\d{3}$"
+            $robot.Name | Should -Not -Be $initialName
+        }
+    }
+
+    It "robot name are unique" {
+        $names = [System.Collections.Generic.HashSet[string]]::new()
+        for ($i = 0; $i -lt 1000; $i++) {
+            $robot = [Robot]::new()
+            $names.Add($robot.Name) | Should -BeTrue
+            $robot.Name | Should -MatchExactly "^[A-Z]{2}\d{3}$"
+        }
+    }
+}