first commit

lib/knife/test.lua

@@ -0,0 +1,128 @@
+local test, testAssert, testError
+
+-- Create a node representing a test section
+local function createNode (parent, description, process)
+    return setmetatable({
+        parent = parent,
+        description = description,
+        process = process,
+        nodes = {},
+        activeNodeIndex = 1,
+        currentNodeIndex = 0,
+        assert = testAssert,
+        error = testError,
+    }, { __call = test })
+end
+
+-- Run a node
+local function runNode (node)
+    node.currentNodeIndex = 0
+    return node:process()
+end
+
+-- Get the root node for a given node
+local function getRootNode (node)
+    local parent = node.parent
+    return parent and getRootNode(parent) or node
+end
+
+-- Update the active child node of the given node
+local function updateActiveNode (node, description, process)
+    local activeNodeIndex = node.activeNodeIndex
+    local nodes = node.nodes
+    local activeNode = nodes[activeNodeIndex]
+
+    if not activeNode then
+        activeNode = createNode(node, description, process)
+        nodes[activeNodeIndex] = activeNode
+    else
+        activeNode.process = process
+    end
+
+    getRootNode(node).lastActiveLeaf = activeNode
+
+    return activeNode
+end
+
+-- Run the active child node of the given node
+local function runActiveNode (node, description, process)
+    local activeNode = updateActiveNode(node, description, process)
+    return runNode(activeNode)
+end
+
+-- Get ancestors of a node, including the node
+local function getAncestors (node)
+    local ancestors = { node }
+    for ancestor in function () return node.parent end do
+        ancestors[#ancestors + 1] = ancestor
+        node = ancestor
+    end
+    return ancestors
+end
+
+-- Print a message describing one execution path in the test scenario
+local function printScenario (node)
+    local ancestors = getAncestors(node)
+    for i = #ancestors, 1, -1 do
+        io.stderr:write(ancestors[i].description or '')
+        io.stderr:write('\n')
+    end
+end
+
+-- Print a message and stop the test scenario when an assertion fails
+local function failAssert (node, description, message)
+    io.stderr:write(message or '')
+    io.stderr:write('\n\n')
+    printScenario(node)
+    io.stderr:write(description or '')
+    io.stderr:write('\n\n')
+    error(message or '', 2)
+end
+
+-- Create a branch node for a test scenario
+test = function (node, description, process)
+    node.currentNodeIndex = node.currentNodeIndex + 1
+    if node.currentNodeIndex == node.activeNodeIndex then
+        return runActiveNode(node, description, process)
+    end
+end
+
+-- Test an assertion
+testAssert = function (self, value, description)
+    if not value then
+        return failAssert(self, description, 'Test failed: assertion failed')
+    end
+    return value
+end
+
+-- Expect function f to fail
+testError = function (self, f, description)
+    if pcall(f) then
+        return failAssert(self, description, 'Test failed: expected error')
+    end
+end
+
+-- Create the root node for a test scenario
+local function T (description, process)
+    local root = createNode(nil, description, process)
+
+    runNode(root)
+    while root.activeNodeIndex <= #root.nodes do
+        local lastActiveBranch = root.lastActiveLeaf.parent
+        lastActiveBranch.activeNodeIndex = lastActiveBranch.activeNodeIndex + 1
+        runNode(root)
+    end
+
+    return root
+end
+
+-- Run any other files passed from CLI.
+if arg and arg[0] and arg[0]:gmatch('test.lua') then
+    _G.T = T
+    for i = 1, #arg do
+        dofile(arg[i])
+    end
+    _G.T = nil
+end
+
+return T