diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0cdf66e..fa67eab 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -38,6 +38,8 @@ jobs:
     - run: npm run test
     - run: npm run coverage
     - run: npm run pushCoverageReport
+      env:
+        COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
 
   publish:
     if: github.event_name == 'release' && github.event.action == 'created'
diff --git a/src/lib/bundle.js b/src/lib/bundle.js
index 0adca71..5639a41 100644
--- a/src/lib/bundle.js
+++ b/src/lib/bundle.js
@@ -1,47 +1,42 @@
 // #!/usr/bin/env node
 'use strict';
-import shell from "shelljs";
 import path from 'path';
 import config from './config';
 import Log from './log';
+import subprocess from './subprocess';
 
 const log = new Log();
 
 var OPENAPI_JSON_PATH = path.join(config.branchPath, 'openapi.json');
 var OPENAPI_YAML_PATH = path.join(config.branchPath, 'openapi.yaml');
 
-const bundleSpec = async () => {
+const bundleSpec = () => {
     log.preview({
         'title': '\nBranch folder',
         'text': `${config.branchPath}/`
     })
-    shell.mkdir('-p', config.branchPath);
-    var specDir = path.join(config.root, 'spec');
-    shell.mkdir('-p', specDir);
 
+    subprocess.makeDirs(config.branchPath);
+    var specDir = path.join(config.root, 'spec');
+    subprocess.makeDirs(specDir);
     var specPath = path.join(config.root, config.apiSpecPath);
-
+    
     log.preview({
         'title': '\nAPI spec (root) location',
         'text': specPath
     })
 
-    shell.cp(specPath, path.join(config.root, 'spec/openapi.yaml'));
+    subprocess.copy(specPath, path.join(config.root, 'spec/openapi.yaml'));
 
     log.info("\nBundling API spec...");
     log.preview({
         'title': "\nStoring bundled 'openapi.json' and 'openapi.yaml' in",
         'text': `${config.branchPath}/\n`
     });
-    shell.exec(
-        `npx openapi bundle -f --output ${OPENAPI_JSON_PATH} ${config.apiSpecPath}`,
-        {silent: true}
-    );
-    shell.exec(
-        `npx openapi bundle -f --output ${OPENAPI_YAML_PATH} ${config.apiSpecPath}`,
-        {silent: true}
-    );
-    shell.rm('-rf', specDir);
+
+    subprocess.exec(`npx openapi bundle -f --output ${OPENAPI_JSON_PATH} ${config.apiSpecPath}`);
+    subprocess.exec(`npx openapi bundle -f --output ${OPENAPI_YAML_PATH} ${config.apiSpecPath}`);
+    subprocess.removeDirs(specDir);
 };
 
 export default bundleSpec;
\ No newline at end of file
diff --git a/src/lib/gh-pages.js b/src/lib/gh-pages.js
index 9e51597..89d69ef 100644
--- a/src/lib/gh-pages.js
+++ b/src/lib/gh-pages.js
@@ -3,27 +3,31 @@ import shell from 'shelljs';
 import config from './config';
 import Log from './log';
 import fs from 'fs';
-
+import subprocess from './subprocess';
 
 const log = new Log();
 
 const fetchPages = () => {
-    shell.rm('-rf', '.ghpages-tmp');
-    shell.mkdir('-p', '.ghpages-tmp');
+
+    subprocess.removeDirs('.ghpages-tmp');
+    subprocess.makeDirs('.ghpages-tmp');
     var startDir = shell.pwd();
-    shell.cd('.ghpages-tmp');
+    subprocess.changeDir('.ghpages-tmp');
+
     log.log(`\nCloning 'gh-pages' branch into '${shell.pwd().stdout}'`);
-    shell.exec(
-        `git clone --depth=1 --branch=gh-pages ${config.repoOrigin} .`,
-        {silent: true}
-    );
-    shell.cp('-Rn', config.branchPathBase, config.root);
+
+    subprocess.exec(`git clone --depth=1 --branch=gh-pages ${config.repoOrigin} .`);
+
+    if (fs.existsSync(config.branchPathBase)) {
+        subprocess.copyDirsN(config.branchPathBase, config.root);
+    }
     if (fs.existsSync(config.docsRoot)) {
-        shell.cp('-Rn', config.docsRoot, config.root);
-        shell.cp('-Rn', 'openapi.*', config.root);
+        subprocess.copyDirsN(config.docsRoot, config.root);
+        subprocess.copyDirsN('openapi.*', config.root);
     }
-    shell.cd(startDir);
-    shell.rm('-rf', '.ghpages-tmp')
+
+    subprocess.changeDir(startDir);
+    subprocess.removeDirs('.ghpages-tmp');
 };
 
 export { fetchPages };
diff --git a/src/lib/redoc-ui.js b/src/lib/redoc-ui.js
index e526168..0f8748d 100644
--- a/src/lib/redoc-ui.js
+++ b/src/lib/redoc-ui.js
@@ -1,10 +1,10 @@
 // #!/usr/bin/env node
 'use strict';
-import shell from 'shelljs';
 import path from 'path';
 import config from './config';
 import themes from './theme';
 import Log from './log';
+import subprocess from './subprocess';
 
 const log = new Log();
 var OPENAPI_YAML_PATH = path.join(config.branchPath, 'openapi.yaml');
@@ -21,16 +21,15 @@ const constructOptsArg = (themes, themeName) => {
 const setupUI = () => {
     var redocOpts = constructOptsArg(themes, config.redocTheme);
     var uiPath = path.join(config.branchPath, config.docsRoot);
-    shell.mkdir('-p', uiPath);
+    subprocess.makeDirs(uiPath);
     var indexPath = path.join(uiPath, 'index.html');
+    
     log.preview({
         title: 'Generating standalone ReDoc HTML',
         text: `${indexPath}\n`
     });
-    shell.exec(
-        `npx redoc-cli bundle --output ${indexPath} ${OPENAPI_YAML_PATH} ${redocOpts}`,
-        {silent: true}
-    );
+    
+    subprocess.exec(`npx redoc-cli bundle --output ${indexPath} ${OPENAPI_YAML_PATH} ${redocOpts}`);
 };
 
 export { setupUI };
\ No newline at end of file
diff --git a/src/lib/subprocess.js b/src/lib/subprocess.js
new file mode 100644
index 0000000..018c6c4
--- /dev/null
+++ b/src/lib/subprocess.js
@@ -0,0 +1,48 @@
+'use strict';
+import shell from 'shelljs';
+
+const cd = "cd";
+const cp = "cp";
+const exec = "exec";
+const mkdir = "mkdir";
+const rm = "rm";
+
+const shellFunctions = {
+    cd: shell.cd,
+    cp: shell.cp,
+    exec: shell.exec,
+    mkdir: shell.mkdir,
+    rm: shell.rm
+}
+
+class Subprocess {
+
+    constructor(command, ...args) {
+        this.command = command;
+        this.args = args;
+    }
+
+    run() {
+        return shellFunctions[this.command](...this.args);
+    }
+
+    runAndAssert() {
+        var exit = this.run()
+        if (exit.code != 0) {
+            throw `Subprocess '${this.command} ${this.args.join(" ")}' `
+                  + `exited with a code of ${exit.code}`;
+        }
+    }
+}
+
+const subprocess = {
+    changeDir: (...args) => new Subprocess(cd, ...args).runAndAssert(),
+    makeDirs: (...args) => new Subprocess(mkdir, '-p', ...args).runAndAssert(),
+    copy: (...args) => new Subprocess(cp, ...args).runAndAssert(),
+    copyDirs: (...args) => new Subprocess(cp, '-R', ...args).runAndAssert(),
+    copyDirsN: (...args) => new Subprocess(cp, '-Rn', ...args).runAndAssert(),
+    removeDirs: (...args) => new Subprocess(rm, '-rf', ...args).runAndAssert(),
+    exec: (...args) => new Subprocess(exec, ...args).runAndAssert()
+}
+
+export default subprocess;
diff --git a/test/mocha/src/lib/testEnvironment.js b/test/mocha/src/lib/testEnvironment.js
index 16729eb..5633622 100644
--- a/test/mocha/src/lib/testEnvironment.js
+++ b/test/mocha/src/lib/testEnvironment.js
@@ -4,7 +4,7 @@ import environment from '@lib/environment';
 describe('environment', () => {
     describe('environment properties', () => {
         it(`assert environment properties are correctly set`, () => {
-            assert.equal(environment.env, 'production');
+            assert.strictEqual(environment.env, 'production');
         })
     })
 })
\ No newline at end of file
diff --git a/test/mocha/src/lib/testSubprocess.js b/test/mocha/src/lib/testSubprocess.js
new file mode 100644
index 0000000..3c57ee7
--- /dev/null
+++ b/test/mocha/src/lib/testSubprocess.js
@@ -0,0 +1,33 @@
+import assert from 'assert';
+import subprocess from '@lib/subprocess';
+
+// test cases for runAndAssert function
+let subprocessTC = [
+    {command: subprocess.changeDir, args: ["/dir/that/doesnt/exist"], expError: true},
+    {command: subprocess.makeDirs, args: [".testtmp"], expError: false},
+    {command: subprocess.copy, args: [".testtmp0", ".testtmp1"], expError: true},
+    {command: subprocess.copyDirs, args: [".testtmp", ".testtmp1"], expError: false},
+    {command: subprocess.copyDirsN, args: [".testtmp", ".testtmp2"], expError: false},
+    {command: subprocess.removeDirs, args: [".testtmp"], expError: false},
+    {command: subprocess.removeDirs, args: [".testtmp1"], expError: false},
+    {command: subprocess.removeDirs, args: [".testtmp2"], expError: false},
+    {command: subprocess.removeDirs, args: ["/dir/that/doesnt/exist"], expError: true},
+    {command: subprocess.exec, args: ['ls -1 > /dev/null'], expError: false},
+    {command: subprocess.exec, args: ['pwd'], expError: false},
+]
+
+describe('subprocess', () => {
+    describe('subprocess', () => {
+        it(`asserts subprocess functions throw an error when expected`, () => {
+            subprocessTC.forEach(tc => {
+                try {
+                    tc.command(...tc.args);
+                    assert.strictEqual(false, tc.expError);
+                } catch (err) {
+                    assert.strictEqual(true, tc.expError);
+                }
+            })
+        })
+    })
+})
+