diff --git a/lib/config/options.js b/lib/config/options.js
index b126ef9ab..387f8a330 100644
--- a/lib/config/options.js
+++ b/lib/config/options.js
@@ -87,7 +87,6 @@ module.exports = root(
 
         sets: map(section({
             files: option({
-                defaultValue: 'gemini',
                 validate: function(value) {
                     if (!_.isArray(value) && !_.isString(value)) {
                         throw new GeminiError('"sets.files" must be an array or string');
@@ -116,9 +115,7 @@ module.exports = root(
                     }
                 }
             })
-        }), {
-            all: {} // Use `all` set with default values if no set specified in config
-        }),
+        })),
 
         browsers: map(section(browserOptions.getPerBrowser()))
     }))
diff --git a/lib/test-reader/files-filter/identity-filter.js b/lib/test-reader/files-filter/identity-filter.js
new file mode 100644
index 000000000..cdc019d5d
--- /dev/null
+++ b/lib/test-reader/files-filter/identity-filter.js
@@ -0,0 +1,9 @@
+'use strict';
+
+const FilesFilter = require('./');
+
+module.exports = class IdentityFilter extends FilesFilter {
+    filter(filesToFilter) {
+        return filesToFilter;
+    }
+};
diff --git a/lib/test-reader/files-filter/index.js b/lib/test-reader/files-filter/index.js
new file mode 100644
index 000000000..70ce3d0e1
--- /dev/null
+++ b/lib/test-reader/files-filter/index.js
@@ -0,0 +1,7 @@
+'use strict';
+
+module.exports = class FilesFilter {
+    filter() {
+        throw new Error('Cannot call method of the base class');
+    }
+};
diff --git a/lib/test-reader/files-filter/intersection-filter.js b/lib/test-reader/files-filter/intersection-filter.js
new file mode 100644
index 000000000..899ab7b29
--- /dev/null
+++ b/lib/test-reader/files-filter/intersection-filter.js
@@ -0,0 +1,19 @@
+'use strict';
+
+const _ = require('lodash');
+
+const FilesFilter = require('./');
+
+module.exports = class IntersectionFilter extends FilesFilter {
+    constructor(files) {
+        super();
+
+        this._files = files;
+    }
+
+    filter(filesToFilter) {
+        return _.isEmpty(filesToFilter)
+            ? this._files
+            : _.intersection(filesToFilter, this._files);
+    }
+};
diff --git a/lib/test-reader/index.js b/lib/test-reader/index.js
index 561c42e90..588871b3e 100644
--- a/lib/test-reader/index.js
+++ b/lib/test-reader/index.js
@@ -1,8 +1,11 @@
 'use strict';
 
-const q = require('q');
+const path = require('path');
 
+const _ = require('lodash');
 const globExtra = require('glob-extra');
+const q = require('q');
+
 const SetCollection = require('./set-collection');
 const Suite = require('../suite');
 const testsApi = require('../tests-api');
@@ -24,10 +27,22 @@ const loadSuites = (sets, emitter) => {
     return rootSuite;
 };
 
+const filesExist = (configSets, cliPaths) => {
+    return !_.isEmpty(configSets) || !_.isEmpty(cliPaths);
+};
+
+const getGeminiPath = (projectRoot) => {
+    return path.resolve(projectRoot, 'gemini');
+};
+
 module.exports = (cli, config, emitter) => {
+    const files = filesExist(config.sets, cli.paths)
+        ? cli.paths
+        : [getGeminiPath(config.system.projectRoot)];
+
     return q.all([
         SetCollection.create(config, cli.sets),
-        globExtra.expandPaths(cli.paths, {formats: ['.js']})
+        globExtra.expandPaths(files, {formats: ['.js']})
     ])
     .spread((sets, paths) => {
         sets.filterFiles(paths);
diff --git a/lib/test-reader/set-collection.js b/lib/test-reader/set-collection.js
index b3945da71..eebd989d3 100644
--- a/lib/test-reader/set-collection.js
+++ b/lib/test-reader/set-collection.js
@@ -9,7 +9,11 @@ const Set = require('./set');
 
 module.exports = class SetCollection {
     static create(config, sets) {
-        const filteredSets = SetCollection._filter(config.sets, sets);
+        let filteredSets = SetCollection._filter(config.sets, sets);
+
+        if (_.isEmpty(filteredSets)) {
+            filteredSets = [{files: {}, browsers: config.getBrowserIds()}];
+        }
 
         return SetCollection._expand(filteredSets, config.system.projectRoot)
             .then((sets) => new SetCollection(sets));
@@ -29,10 +33,13 @@ module.exports = class SetCollection {
         const unknownSets = _.difference(setsToUse, _.keys(sets));
 
         if (!_.isEmpty(unknownSets)) {
-            throw new GeminiError(
-                `No such sets: ${unknownSets.join(', ')}. Use one of the sets, specified ` +
-                `in config file: ${_.keys(sets).join(', ')}`
-            );
+            let error = `No such sets: ${unknownSets.join(', ')}.`;
+
+            if (!_.isEmpty(sets)) {
+                error += ` Use one of the sets, specified in config file: ${_.keys(sets).join(', ')}`;
+            }
+
+            throw new GeminiError(error);
         }
     }
 
diff --git a/lib/test-reader/set.js b/lib/test-reader/set.js
index 5f8b70446..832ed2855 100644
--- a/lib/test-reader/set.js
+++ b/lib/test-reader/set.js
@@ -2,6 +2,9 @@
 
 const _ = require('lodash');
 
+const IdentityFilter = require('./files-filter/identity-filter');
+const IntersectionFilter = require('./files-filter/intersection-filter');
+
 module.exports = class Set {
     static create(set) {
         return new Set(set);
@@ -9,6 +12,10 @@ module.exports = class Set {
 
     constructor(set) {
         this._set = set;
+
+        this._filesFilter = _.isEmpty(this._set.files)
+            ? new IdentityFilter()
+            : new IntersectionFilter(this._set.files);
     }
 
     getFiles() {
@@ -20,8 +27,6 @@ module.exports = class Set {
     }
 
     filterFiles(files) {
-        if (!_.isEmpty(files)) {
-            this._set.files = _.intersection(files, this._set.files);
-        }
+        this._set.files = this._filesFilter.filter(files);
     }
 };
diff --git a/test/unit/config-options/sets.test.js b/test/unit/config-options/sets.test.js
index 77d22993a..dd15245bd 100644
--- a/test/unit/config-options/sets.test.js
+++ b/test/unit/config-options/sets.test.js
@@ -1,12 +1,14 @@
 'use strict';
-var parser = require('lib/config/options'),
-    GeminiError = require('lib/errors/gemini-error'),
-    _ = require('lodash');
-
-describe('config.sets', function() {
-    ///
-    function createConfig(opts) {
-        var REQUIRED_OPTIONS = {
+
+const MissingOptionError = require('gemini-configparser').MissingOptionError;
+const _ = require('lodash');
+
+const parser = require('lib/config/options');
+const GeminiError = require('lib/errors/gemini-error');
+
+describe('config.sets', () => {
+    const createConfig = (opts) => {
+        const REQUIRED_OPTIONS = {
             system: {
                 projectRoot: '/some/path'
             },
@@ -14,28 +16,28 @@ describe('config.sets', function() {
             desiredCapabilities: {}
         };
 
-        var options = _.extend({}, REQUIRED_OPTIONS, opts);
+        const options = _.extend({}, REQUIRED_OPTIONS, opts);
 
         return parser({
             options: options,
             env: {},
             argv: []
         });
-    }
+    };
 
-    describe('files', function() {
-        it('should be `gemini` by default', function() {
-            var config = createConfig({
-                sets: {
-                    someSet: {}
-                }
-            });
-
-            assert.deepEqual(config.sets.someSet.files, ['gemini']);
+    describe('files', () => {
+        it('should throw an error if files are not specified', () => {
+            assert.throws(() => {
+                createConfig({
+                    sets: {
+                        someSet: {}
+                    }
+                });
+            }, MissingOptionError);
         });
 
-        it('should convert string to array of strings', function() {
-            var config = createConfig({
+        it('should convert string to array of strings', () => {
+            const config = createConfig({
                 sets: {
                     someSet: {
                         files: 'some/path'
@@ -46,8 +48,8 @@ describe('config.sets', function() {
             assert.deepEqual(config.sets.someSet.files, ['some/path']);
         });
 
-        it('should not accept non-string arrays', function() {
-            assert.throws(function() {
+        it('should not accept non-string arrays', () => {
+            assert.throws(() => {
                 createConfig({
                     sets: {
                         someSet: {
@@ -58,8 +60,8 @@ describe('config.sets', function() {
             }, GeminiError);
         });
 
-        it('should accept array with strings', function() {
-            var config = createConfig({
+        it('should accept array with strings', () => {
+            const config = createConfig({
                 sets: {
                     someSet: {
                         files: [
@@ -77,26 +79,29 @@ describe('config.sets', function() {
         });
     });
 
-    describe('browsers', function() {
-        it('should contain all browsers by default', function() {
+    describe('browsers', () => {
+        it('should contain all browsers by default', () => {
             var config = createConfig({
                 browsers: {
                     b1: {},
                     b2: {}
                 },
                 sets: {
-                    someSet: {}
+                    someSet: {
+                        files: ['some/path']
+                    }
                 }
             });
 
             assert.deepEqual(config.sets.someSet.browsers, ['b1', 'b2']);
         });
 
-        it('should not accept non-arrays', function() {
-            assert.throws(function() {
+        it('should not accept non-arrays', () => {
+            assert.throws(() => {
                 createConfig({
                     sets: {
                         someSet: {
+                            files: ['some/path'],
                             browsers: 'something'
                         }
                     }
@@ -104,8 +109,8 @@ describe('config.sets', function() {
             }, GeminiError);
         });
 
-        it('should not accept unknown browsers', function() {
-            assert.throws(function() {
+        it('should not accept unknown browsers', () => {
+            assert.throws(() => {
                 createConfig({
                     browsers: {
                         b1: {},
@@ -113,6 +118,7 @@ describe('config.sets', function() {
                     },
                     sets: {
                         someSet: {
+                            files: ['some/path'],
                             browsers: ['b3']
                         }
                     }
@@ -120,17 +126,19 @@ describe('config.sets', function() {
             }, GeminiError);
         });
 
-        it('should accept configured browsers', function() {
-            var config = createConfig({
+        it('should accept configured browsers', () => {
+            const config = createConfig({
                 browsers: {
                     b1: {},
                     b2: {}
                 },
                 sets: {
                     set1: {
+                        files: ['some/path'],
                         browsers: ['b1']
                     },
                     set2: {
+                        files: ['other/path'],
                         browsers: ['b2']
                     }
                 }
@@ -141,15 +149,14 @@ describe('config.sets', function() {
         });
     });
 
-    it('should have `all` set with default values if no set specified', function() {
-        var config = createConfig({
+    it('should not have default set if sets are not specified', () => {
+        const config = createConfig({
             browsers: {
                 b1: {},
                 b2: {}
             }
         });
 
-        assert.deepEqual(config.sets.all.files, ['gemini']);
-        assert.deepEqual(config.sets.all.browsers, ['b1', 'b2']);
+        assert.deepEqual(config.sets, {});
     });
 });
diff --git a/test/unit/test-reader/index.test.js b/test/unit/test-reader/index.test.js
index 90089962c..0518a7ae8 100644
--- a/test/unit/test-reader/index.test.js
+++ b/test/unit/test-reader/index.test.js
@@ -100,6 +100,17 @@ describe('test-reader', () => {
         });
     });
 
+    it('should use gemini folder if sets are not specified in config and paths are not passed', () => {
+        const config = {
+            getBrowserIds: () => []
+        };
+
+        globExtra.expandPaths.withArgs(['/root/gemini']).returns(q(['/root/gemini/file.js']));
+
+        return readTests_({config})
+            .then(() => assert.calledWith(utils.requireWithNoCache, '/root/gemini/file.js'));
+    });
+
     it('should load suites related to sets from config', () => {
         const config = {
             sets: {
diff --git a/test/unit/test-reader/set-collection.test.js b/test/unit/test-reader/set-collection.test.js
index 9b0e1bc3a..6d87da28d 100644
--- a/test/unit/test-reader/set-collection.test.js
+++ b/test/unit/test-reader/set-collection.test.js
@@ -20,6 +20,7 @@ describe('set-collection', () => {
     const mkConfigStub = (opts) => {
         return _.defaults(opts || {}, {
             sets: opts.sets || {},
+            getBrowserIds: opts.getBrowserIds,
             system: {
                 projectRoot: '/root'
             }
@@ -32,6 +33,21 @@ describe('set-collection', () => {
 
     afterEach(() => sandbox.restore());
 
+    describe('sets are not specified in config', () => {
+        it('should throw an error if an unknown set was passed', () => {
+            assert.throws(() => SetCollection.create(mkConfigStub(), ['unknown-set'], /unknown-set/));
+        });
+
+        it('should create new set with empty files and browsers from config', () => {
+            sandbox.stub(Set, 'create').returns(mkSetStub());
+
+            const getBrowserIds = sandbox.stub().returns(['b1', 'b2']);
+
+            return SetCollection.create(mkConfigStub({getBrowserIds}))
+                .then(() => assert.calledWith(Set.create, {files: [], browsers: ['b1', 'b2']}));
+        });
+    });
+
     it('should create collection for specified sets', () => {
         const config = mkConfigStub({
             sets: {
@@ -94,10 +110,10 @@ describe('set-collection', () => {
             }
         });
 
-        assert.throws(() => SetCollection.create(config, ['set3']), /set3(.+) set1, set2/);
+        assert.throws(() => SetCollection.create(config, ['unknown-set']), /unknown-set(.+) set1, set2/);
     });
 
-    it('should filter sets files by passed files', () => {
+    it('should filter passed files if sets are specified in config', () => {
         const sets = {
             set1: mkSetStub(),
             set2: mkSetStub()
diff --git a/test/unit/test-reader/set.test.js b/test/unit/test-reader/set.test.js
index 5471afc04..d4ecd4680 100644
--- a/test/unit/test-reader/set.test.js
+++ b/test/unit/test-reader/set.test.js
@@ -46,5 +46,14 @@ describe('Set', () => {
 
             assert.deepEqual(files, ['some/path/file.js']);
         });
+
+        it('should return passed files if set files are empty', () => {
+            set = new Set({files: []});
+            set.filterFiles(['some/path/file.js']);
+
+            const files = set.getFiles();
+
+            assert.deepEqual(files, ['some/path/file.js']);
+        });
     });
 });