Add unit testing Github action workflow

.github/workflows/tests.yaml

@@ -0,0 +1,27 @@
+name: Test
+on:
+- push
+- pull_request
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        lua_version: ["5.4", "5.3", "5.2", "5.1"]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Set up Lua
+        uses: luarocks/gh-actions-lua@master
+        with:
+          luaVersion: ${{ matrix.lua_version }}
+      - name: Set up LuaRocks
+        uses: luarocks/gh-actions-luarocks@master
+      - name: Setup dependencies
+        run: luarocks install luaunit
+      - name: Build luarock
+        run: luarocks build streams-scm-1.rockspec
+      - name: Run tests
+        run: luarocks test

streams-scm-1.rockspec

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+rockspec_format = "3.0"
+package = "streams"
+version = "scm-1"
+
+source = {
+  url = "git+https://github.com/rbaltrusch/stream.lua",
+  branch = "master", -- this will be replaced by the release workflow
+}
+
+description = {
+   summary = "Iterator-chaining library implementing common functional programming patterns such as `map`, `filter`, and `reduce`",
+   detailed = [[
+      This library provides a Java-like `Stream` class that provides a fluent interface of lazily-computed and chainable iterator operations such as `map`, `filter`, and `reduce`. For example:
+
+      ```lua
+      local fn = require "stream"
+      fn.stream{2, 3, 4, 7}
+          :filter(function(x) return x % 2 == 0 end)
+          :map(function(x) return x ^ 2 end)
+          :collect()  -- {4, 16}
+      ```
+   ]],
+   homepage = "https://github.com/rbaltrusch/stream.lua",
+   issues_url = "https://github.com/rbaltrusch/stream.lua/issues",
+   license = "MIT",
+   maintainer = "Richard Baltrusch",
+}
+
+dependencies = {
+   "lua >= 5.1"
+}
+
+test_dependencies = {
+  "luaunit",
+}
+
+build = {
+  type = "builtin",
+  modules = {
+    stream = "stream.lua",
+  },
+}
+
+test = {
+  type = "command",
+  script = "tests/run_tests.lua",
+}