test: Port Set test to Busted

spec/set_spec.lua

@@ -0,0 +1,84 @@
+local Set = require("pl.Set")
+
+describe("pl.Set", function ()
+
+  local s = Set()
+  local s1_2 = Set({ 1, 2 })
+  local s1_2_3 = Set({ 1, 2, 3 })
+  local s1_3 = Set({ 1, 3 })
+  local s2 = Set({ 2 })
+  local s2_1 = Set({ 2, 1 })
+  local s2_3 = Set({ 2, 3 })
+  local s3 = Set({ 3 })
+  local sm = Set({ "foo", "bar" })
+
+  it("should produce a set object", function ()
+    assert.is.same({ true, true }, s1_2)
+  end)
+
+  it("should produce identical sets for any ordered input", function ()
+    assert.is.same(s1_2, s2_1)
+  end)
+
+  describe("should have an operator for", function ()
+
+    it("union", function ()
+      assert.is.same(s1_2_3, s1_2 + s3)
+      assert.is.same(s1_2_3, s1_2 + 3)
+    end)
+
+    it("intersection", function ()
+      assert.is.same(s2, s1_2 * s2_3)
+    end)
+
+    it("difference", function ()
+      assert.is.same(s2_1, s1_2_3 - s3)
+      assert.is.same(s2_3, s1_2_3 - 1)
+    end)
+
+    it("symmetric difference", function ()
+      assert.is.same(s1_3, s1_2 ^ s2_3)
+    end)
+
+    it("tostring", function ()
+      -- Cannot test multi-entry sets because of non-deterministic key order
+      assert.is.same('[2]', tostring(s2))
+    end)
+
+  end)
+
+  describe("should provide functions", function ()
+
+    it("isempty", function ()
+      assert.is.truthy(Set.isempty(s))
+      assert.is.falsy(Set.isempty(s3))
+    end)
+
+    it("set", function ()
+      local m = Set()
+      Set.set(m, 'foo', true)
+      m.bar = true
+      assert.is.same(m, sm)
+      assert.is_not.same(m, s1_2)
+    end)
+
+  end)
+
+  describe("should have a comparison operator for", function ()
+
+    it("supersets/subsets than", function ()
+      assert.is.truthy(s1_2 > s2)
+      assert.is.falsy(s1_3 > s2)
+      assert.is.falsy(s1_2 > s2_3)
+      assert.is.truthy(s1_2 < s1_2_3)
+      assert.is.falsy(s1_2_3 < s1_2)
+    end)
+
+    it("equality", function ()
+      assert.is.truthy(s1_2 == s2_1)
+      assert.is.falsy(s1_2 == s2_3)
+    end)
+
+  end)
+
+end)