Add e2e tests for yank/paste

e2e/lib/clipboard.js

@@ -0,0 +1,63 @@
+'use strict';
+
+const { spawn } = require('child_process');
+
+const readLinux = () => {
+  let stdout = '', stderr = '';
+  return new Promise((resolve, reject) => {
+    let xsel = spawn('xsel', ['--clipboard', '--output']);
+    xsel.stdout.on('data', (data) => {
+      stdout += data;
+    });
+    xsel.stderr.on('data', (data) => {
+      stderr += data;
+    });
+    xsel.on('close', (code) => {
+      if (code !== 0) {
+        throw new Error(`xsel returns ${code}: ${stderr}`)
+      }
+      resolve(stdout);
+    });
+  });
+};
+
+const writeLinux = (data) => {
+  let stdout = '', stderr = '';
+  return new Promise((resolve, reject) => {
+    let xsel = spawn('xsel', ['--clipboard', '--input']);
+    xsel.stderr.on('data', (data) => {
+      stderr += data;
+    });
+    xsel.on('close', (code) => {
+      if (code !== 0) {
+        throw new Error(`xsel returns ${code}: ${stderr}`)
+      }
+      resolve();
+    });
+    xsel.stdin.write(data);
+    xsel.stdin.end();
+  });
+};
+
+const unsupported = (os) => {
+  return () => {
+    throw new Error(`Unsupported os: ${os}`);
+  };
+};
+
+const detect = () => {
+  switch (process.platform) {
+    case 'linux':
+      return {
+        read: readLinux,
+        write: writeLinux,
+      };
+    default:
+      return {
+        read: unsupported(process.platform),
+        write: unsupported(process.platform),
+      };
+  }
+}
+
+module.exports = detect();