Update bank-account tests (#581)

Author: ryanplusplus

exercises/practice/bank-account/.meta/example.lua

@@ -1,28 +1,36 @@
 local BankAccount = {}
 
+function BankAccount:open()
+  assert(not self._open)
+  self._open = true
+  self._balance = 0
+end
+
 function BankAccount:balance()
-  return self._value
+  assert(self._open)
+  return self._balance
 end
 
 function BankAccount:deposit(amount)
-  assert(not self._closed)
+  assert(self._open)
   assert(amount > 0)
-  self._value = self._value + amount
+  self._balance = self._balance + amount
 end
 
 function BankAccount:withdraw(amount)
-  assert(not self._closed)
+  assert(self._open)
   assert(amount > 0)
-  assert(self._value - amount > 0)
-  self._value = self._value - amount
+  assert(self._balance - amount >= 0)
+  self._balance = self._balance - amount
 end
 
 function BankAccount:close(amount)
-  self._closed = true
+  assert(self._open)
+  self._open = false
 end
 
 function BankAccount:new()
-  local o = setmetatable({ _value = 0 }, self)
+  local o = setmetatable({ _balance = 0, _open = false }, self)
   self.__index = self
   return o
 end

exercises/practice/bank-account/.meta/spec_generator.lua

@@ -0,0 +1,29 @@
+local function render_operation(operation)
+  if operation.amount then
+    return 'account:' .. operation.operation .. '(' .. operation.amount .. ')'
+  else
+    return 'account:' .. operation.operation .. '()'
+  end
+end
+
+return {
+  module_name = 'BankAccount',
+
+  generate_test = function(case)
+    local lines = { 'local account = BankAccount:new()' }
+
+    for i, operation in ipairs(case.input.operations) do
+      if i == #case.input.operations then
+        if type(case.expected) == 'table' and case.expected.error then
+          table.insert(lines, 'assert.has_error(function() ' .. render_operation(operation) .. ' end)')
+        else
+          table.insert(lines, 'assert.equal(' .. case.expected .. ', ' .. render_operation(operation) .. ')')
+        end
+      else
+        table.insert(lines, render_operation(operation))
+      end
+    end
+
+    return table.concat(lines, '\n')
+  end
+}

exercises/practice/bank-account/.meta/tests.toml

@@ -0,0 +1,62 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[983a1528-4ceb-45e5-8257-8ce01aceb5ed]
+description = "Newly opened account has zero balance"
+
+[e88d4ec3-c6bf-4752-8e59-5046c44e3ba7]
+description = "Single deposit"
+
+[3d9147d4-63f4-4844-8d2b-1fee2e9a2a0d]
+description = "Multiple deposits"
+
+[08f1af07-27ae-4b38-aa19-770bde558064]
+description = "Withdraw once"
+
+[6f6d242f-8c31-4ac6-8995-a90d42cad59f]
+description = "Withdraw twice"
+
+[45161c94-a094-4c77-9cec-998b70429bda]
+description = "Can do multiple operations sequentially"
+
+[f9facfaa-d824-486e-8381-48832c4bbffd]
+description = "Cannot check balance of closed account"
+
+[7a65ba52-e35c-4fd2-8159-bda2bde6e59c]
+description = "Cannot deposit into closed account"
+
+[a0a1835d-faae-4ad4-a6f3-1fcc2121380b]
+description = "Cannot deposit into unopened account"
+
+[570dfaa5-0532-4c1f-a7d3-0f65c3265608]
+description = "Cannot withdraw from closed account"
+
+[c396d233-1c49-4272-98dc-7f502dbb9470]
+description = "Cannot close an account that was not opened"
+
+[c06f534f-bdc2-4a02-a388-1063400684de]
+description = "Cannot open an already opened account"
+
+[0722d404-6116-4f92-ba3b-da7f88f1669c]
+description = "Reopened account does not retain balance"
+
+[ec42245f-9361-4341-8231-a22e8d19c52f]
+description = "Cannot withdraw more than deposited"
+
+[4f381ef8-10ef-4507-8e1d-0631ecc8ee72]
+description = "Cannot withdraw negative"
+
+[d45df9ea-1db0-47f3-b18c-d365db49d938]
+description = "Cannot deposit negative"
+
+[ba0c1e0b-0f00-416f-8097-a7dfc97871ff]
+description = "Can handle concurrent transactions"
+include = false

exercises/practice/bank-account/bank-account_spec.lua

@@ -1,95 +1,136 @@
 local BankAccount = require('bank-account')
 
 describe('bank-account', function()
-  it('should have a balance of zero after opening a new account', function()
+  it('newly opened account has zero balance', function()
     local account = BankAccount:new()
+    account:open()
     assert.equal(0, account:balance())
   end)
 
-  it('should allow deposits', function()
+  it('single deposit', function()
     local account = BankAccount:new()
-    account:deposit(45)
-    assert.equal(45, account:balance())
+    account:open()
+    account:deposit(100)
+    assert.equal(100, account:balance())
   end)
 
-  it('should allow multiple deposits', function()
+  it('multiple deposits', function()
     local account = BankAccount:new()
-    account:deposit(10)
-    account:deposit(25)
-    assert.equal(35, account:balance())
+    account:open()
+    account:deposit(100)
+    account:deposit(50)
+    assert.equal(150, account:balance())
   end)
 
-  it('should require deposits to be positive', function()
+  it('withdraw once', function()
     local account = BankAccount:new()
-    assert.has.errors(function()
-      account:deposit(0)
-    end)
-    assert.has.errors(function()
-      account:deposit(-1)
-    end)
+    account:open()
+    account:deposit(100)
+    account:withdraw(75)
+    assert.equal(25, account:balance())
   end)
 
-  it('should allow withdrawals', function()
+  it('withdraw twice', function()
     local account = BankAccount:new()
-    account:deposit(20)
-    account:withdraw(10)
-    assert.equal(10, account:balance())
+    account:open()
+    account:deposit(100)
+    account:withdraw(80)
+    account:withdraw(20)
+    assert.equal(0, account:balance())
   end)
 
-  it('should allow multiple withdrawals', function()
+  it('can do multiple operations sequentially', function()
     local account = BankAccount:new()
+    account:open()
     account:deposit(100)
-    account:withdraw(10)
-    account:withdraw(25)
-    assert.equal(65, account:balance())
+    account:deposit(110)
+    account:withdraw(200)
+    account:deposit(60)
+    account:withdraw(50)
+    assert.equal(20, account:balance())
   end)
 
-  it('should require withdrawals to be positive', function()
+  it('cannot check balance of closed account', function()
     local account = BankAccount:new()
-    account:deposit(100)
-    assert.has.errors(function()
-      account:withdraw(0)
-    end)
-    assert.has.errors(function()
-      account:withdraw(-1)
+    account:open()
+    account:close()
+    assert.has_error(function()
+      account:balance()
     end)
   end)
 
-  it('should not allow accounts to be overdrawn', function()
+  it('cannot deposit into closed account', function()
     local account = BankAccount:new()
-    assert.has.errors(function()
-      account:withdraw(1)
+    account:open()
+    account:close()
+    assert.has_error(function()
+      account:deposit(50)
     end)
   end)
 
-  it('should allow multiple independent accounts to be created', function()
-    local account1 = BankAccount:new()
-    local account2 = BankAccount:new()
-    account1:deposit(100)
-    account2:deposit(42)
-    assert.are.equal(100, account1:balance())
-    assert.are.equal(42, account2:balance())
+  it('cannot deposit into unopened account', function()
+    local account = BankAccount:new()
+    assert.has_error(function()
+      account:deposit(50)
+    end)
   end)
 
-  it('should allow accounts to be closed', function()
+  it('cannot withdraw from closed account', function()
     local account = BankAccount:new()
+    account:open()
     account:close()
+    assert.has_error(function()
+      account:withdraw(50)
+    end)
   end)
 
-  it('should not allow deposits to a closed account', function()
+  it('cannot close an account that was not opened', function()
     local account = BankAccount:new()
-    account:close()
-    assert.has.errors(function()
-      account:deposit(1)
+    assert.has_error(function()
+      account:close()
+    end)
+  end)
+
+  it('cannot open an already opened account', function()
+    local account = BankAccount:new()
+    account:open()
+    assert.has_error(function()
+      account:open()
     end)
   end)
 
-  it('should not allow withdrawals from a closed account', function()
+  it('reopened account does not retain balance', function()
     local account = BankAccount:new()
-    account:deposit(10)
+    account:open()
+    account:deposit(50)
     account:close()
-    assert.has.errors(function()
-      account:withdraw(1)
+    account:open()
+    assert.equal(0, account:balance())
+  end)
+
+  it('cannot withdraw more than deposited', function()
+    local account = BankAccount:new()
+    account:open()
+    account:deposit(25)
+    assert.has_error(function()
+      account:withdraw(50)
+    end)
+  end)
+
+  it('cannot withdraw negative', function()
+    local account = BankAccount:new()
+    account:open()
+    account:deposit(100)
+    assert.has_error(function()
+      account:withdraw(-50)
+    end)
+  end)
+
+  it('cannot deposit negative', function()
+    local account = BankAccount:new()
+    account:open()
+    assert.has_error(function()
+      account:deposit(-50)
     end)
   end)
 end)