Implement hashStream

Add a hashStream method to lib/hash that does the same as hashFile only
with a stream instead of a file path and implement tests for both of
these methods.

lib/hash.js

@@ -1,10 +1,13 @@
 const crypto = require('crypto');
 const fs = require('fs');
 
+
 /**
- * Returns a promise that resolves to the SHA1 hash of the file given by path
+ * Returns a promise that resolves to the SHA1 hash of the stream given
+ *
+ * @param stream - Node stream of the content to hash.
  */
-exports.hashFile = function(path) {
+function hashStream(stream) {
 	return new Promise(function(resolve, reject) {
 		let hasher = crypto.createHash('sha1')
 		hasher.setEncoding('hex')
@@ -12,11 +15,25 @@ exports.hashFile = function(path) {
 			resolve(hasher.read());
 		});
 
-		let stream = fs.createReadStream(path);
 		stream.on('error', function(error) {
 			// the docs doesn't say anything about what's passed on error
 			reject(error);
 		});
+
 		stream.pipe(hasher);
 	});
 }
+
+/**
+ * Returns a promise that resolves to the SHA1 hash of the file given by path
+ *
+ * @param {string} path - Path to the file to hash.
+ */
+function hashFile(path) {
+	return hashStream(fs.createReadStream(path));
+}
+
+module.exports = {
+	hashStream,
+	hashFile,
+}

test/file/hash.txt

@@ -0,0 +1 @@
+The quick brown fox jumps over the lazy dog

test/lib/hash.js

@@ -0,0 +1,24 @@
+const assert = require('assert').strict;
+const fs = require('fs');
+const path = require('path');
+const stream = require('stream');
+
+const hash = require('lib/hash');
+
+
+describe("lib/hash", function() {
+	describe("hashStream()", function() {
+		it("should hash a stream of bytes", async function() {
+			let stream = fs.createReadStream(path.join("test", "file", "hash.txt"));
+			let result = await hash.hashStream(stream);
+			assert.equal(result, "be417768b5c3c5c1d9bcb2e7c119196dd76b5570");
+		});
+	});
+
+	describe("hashFile()", function() {
+		it("should hash a file", async function() {
+			let result = await hash.hashFile(path.join("test", "file", "hash.txt"));
+			assert.equal(result, "be417768b5c3c5c1d9bcb2e7c119196dd76b5570");
+		});
+	});
+});

test/missing.js

@@ -4,7 +4,6 @@
 require('lib/clusterTools');
 require('lib/dole_nn_base');
 require('lib/getInstances');
-require('lib/hash');
 require('lib/manager/instanceManager');
 require('lib/manager/modManager');
 require('lib/manager/pluginManager');