Merge pull request #51 from mkantor/examples-with-snapshots

Add some example programs

Author: mkantor

README.md

@@ -12,6 +12,8 @@ npm run build
 echo '{@runtime context => :context.program.start_time}' | ./please --output-format=json
 ```
 
+There are more example programs in [`./examples`](./examples).
+
 ## What This Repository Is
 
 **This implementation of Please is a proof of concept**. There are bugs and

examples/.snapshot

@@ -0,0 +1,100 @@
+exports[`examples > fibonacci.plz --input="not a number" > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz --input="not a number" > stdout 1`] = `
+"input must be a natural number"
+
+`;
+
+exports[`examples > fibonacci.plz --input=-1 > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz --input=-1 > stdout 1`] = `
+"input must be a natural number"
+
+`;
+
+exports[`examples > fibonacci.plz --input=0 > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz --input=0 > stdout 1`] = `
+0
+
+`;
+
+exports[`examples > fibonacci.plz --input=1 > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz --input=1 > stdout 1`] = `
+1
+
+`;
+
+exports[`examples > fibonacci.plz --input=10 > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz --input=10 > stdout 1`] = `
+55
+
+`;
+
+exports[`examples > fibonacci.plz --input=2 > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz --input=2 > stdout 1`] = `
+1
+
+`;
+
+exports[`examples > fibonacci.plz > stderr 1`] = `
+
+`;
+
+exports[`examples > fibonacci.plz > stdout 1`] = `
+"missing input argument"
+
+`;
+
+exports[`examples > kitchen-sink.plz > stderr 1`] = `
+"this goes to stderr"
+
+`;
+
+exports[`examples > kitchen-sink.plz > stdout 1`] = `
+{
+  foo: bar
+  bar: bar
+  sky_is_blue: true
+  colors: {
+    red
+    green
+    blue
+  }
+  two: 2
+  add_one: :integer.add(1)
+  three: 3
+  function: x => {
+    value: :x
+  }
+  conditional_value: {
+    value: 2
+  }
+  side_effect: "this goes to stderr"
+}
+
+`;
+
+exports[`examples > lookup-environment-variable.plz > stderr 1`] = `
+
+`;
+
+exports[`examples > lookup-environment-variable.plz > stdout 1`] = `
+{}
+
+`;

examples/fibonacci.plz

@@ -0,0 +1,24 @@
+{
+  fibonacci: n => {
+    @if :integer.less_than(2)(:n)
+    then: :n
+    else: :integer.add(
+      :fibonacci(:integer.subtract(2)(:n))
+    )(
+      :fibonacci(:integer.subtract(1)(:n))
+    )
+  }
+
+  input: { @runtime context => :context.arguments.lookup(input) }
+
+  output: :apply(:input)(
+    :match({
+      none: _ => "missing input argument"
+      some: input => {
+        @if :natural_number.is(:input)
+        then: :fibonacci(:input)
+        else: "input must be a natural number"
+      }
+    })
+  )
+}.output

examples/kitchen-sink.plz

@@ -0,0 +1,13 @@
+{
+  // a comment
+  foo: bar
+  bar: :foo
+  sky_is_blue: :boolean.not(false)
+  colors: { red green blue }
+  two: :integer.add(1)(1)
+  add_one: :integer.add(1)
+  three: :add_one(:two)
+  function: x => { value: :x }
+  conditional_value: :function({ @if :sky_is_blue :two :three })
+  side_effect: { @runtime context => :context.log("this goes to stderr") }
+}

examples/lookup-environment-variable.plz

@@ -0,0 +1,15 @@
+{@runtime context =>
+  :flow({
+    :context.arguments.lookup
+    :match({
+      none: {}
+      some: :flow({
+        :context.environment.lookup
+        :match({
+          none: {}
+          some: :identity
+        })
+      })
+    })
+  })(variable)
+}

package.json

@@ -12,7 +12,8 @@
     "build": "tsc --build tsconfig.app.json --force",
     "build:tests": "tsc --project tsconfig.app.json --outDir dist-test --declarationDir dist && tsc --build tsconfig.test.json",
     "clean": "rm -rf dist* *.tsbuildinfo",
-    "test": "npm run build:tests && node --test"
+    "test": "npm run build:tests && node --test --experimental-test-snapshots",
+    "test-update-snapshots": "npm run build:tests && node --test --test-update-snapshots --experimental-test-snapshots"
   },
   "devDependencies": {
     "@types/node": "^22.5.5",

src/examples.test.ts

@@ -0,0 +1,88 @@
+import { exec } from 'node:child_process'
+import { promises as fs } from 'node:fs'
+import path from 'node:path'
+import test, { snapshot, suite } from 'node:test'
+
+// All examples will be tested with no additional command-line arguments. To
+// also test with specific sets of arguments, add them here:
+const additionalCommandLineArguments: Readonly<
+  Record<string, readonly string[]>
+> = {
+  'fibonacci.plz': [
+    '--input=0',
+    '--input=1',
+    '--input=2',
+    '--input=10',
+    '--input="not a number"',
+    '--input=-1',
+  ],
+}
+
+snapshot.setResolveSnapshotPath(_ =>
+  path.join(import.meta.dirname, '..', 'examples', '.snapshot'),
+)
+
+const exampleDirectoryPath = path.join(import.meta.dirname, '..', 'examples')
+const pleasePath = path.join(
+  import.meta.dirname,
+  'language',
+  'cli',
+  'please.js',
+)
+
+suite('examples', async () => {
+  const exampleFileNames = (await fs.readdir(exampleDirectoryPath)).filter(
+    fileName => fileName.endsWith('.plz'),
+  )
+  for (const exampleFileName of exampleFileNames) {
+    const setsOfCommandLineArguments = [
+      '', // Always test with no arguments.
+      ...(additionalCommandLineArguments[exampleFileName] ?? []),
+    ] as const
+
+    for (const commandLineArguments of setsOfCommandLineArguments) {
+      const exampleFilePath = path.join(exampleDirectoryPath, exampleFileName)
+      test(
+        exampleFileName.concat(
+          commandLineArguments === '' ? '' : ` ${commandLineArguments}`,
+        ),
+        _ =>
+          new Promise((resolve, reject) => {
+            const _childProcess = exec(
+              `cat "${exampleFilePath}" | node "${pleasePath}" --no-color --output-format=plz ${commandLineArguments}`,
+              (error, stdout, stderr) => {
+                // `error` is an `ExecException` when exit status is nonzero.
+                if (error !== null) {
+                  reject(error)
+                } else {
+                  Promise.all([
+                    test('stdout', t =>
+                      t.assert.snapshot(stdout, snapshotOptions)),
+                    test('stderr', t =>
+                      t.assert.snapshot(stderr, snapshotOptions)),
+                  ])
+                    .then(_ => resolve(undefined))
+                    .catch(reject)
+                }
+              },
+            )
+          }),
+      )
+    }
+  }
+})
+
+// Expect snapshots to already be strings.
+const snapshotOptions = {
+  serializers: [
+    (value: unknown) => {
+      if (typeof value !== 'string') {
+        throw new Error(
+          `snapshot was not a string (was \`${JSON.stringify(value)}\`)`,
+        )
+      } else {
+        return value
+      }
+    },
+  ],
+}