diff --git a/lib/jsdoc/tag.js b/lib/jsdoc/tag.js
index 349b15c5..ac261585 100644
--- a/lib/jsdoc/tag.js
+++ b/lib/jsdoc/tag.js
@@ -41,13 +41,14 @@ function trim(text, newlines) {
     @param {object=} meta
  */
 exports.Tag = function(tagTitle, tagBody, meta) {
-    var tagDef = jsdoc.tag.dictionary.lookUp(tagTitle);
     meta = meta  || {};
     
     this.originalTitle = trim(tagTitle);
     
     /** The title part of the tag: @title text */
     this.title = jsdoc.tag.dictionary.normalise( this.originalTitle );
+
+    var tagDef = jsdoc.tag.dictionary.lookUp(this.title);
     
     /** The text part of the tag: @title text */
     this.text = trim(tagBody, tagDef.keepsWhitespace);
@@ -65,10 +66,15 @@ exports.Tag = function(tagTitle, tagBody, meta) {
             
             var tagType = jsdoc.tag.type.parse(this.text, tagDef.canHaveName, tagDef.canHaveType);
 
-            if (tagType.type && tagType.type.length) {
-                this.value.type = {
-                    names: tagType.type
-                };
+            // It is possible for a tag to *not* have a type but still have
+            // optional or defaultvalue, e.g. '@param [foo]'.
+            // Although tagType.type.length == 0 we should still copy the other properties.
+            if (tagType.type) {
+                if (tagType.type.length) {
+                    this.value.type = {
+                        names: tagType.type
+                    };
+                }
                 this.value.optional = tagType.optional;
                 this.value.nullable = tagType.nullable;
                 this.value.variable = tagType.variable;
diff --git a/lib/jsdoc/tag/dictionary.js b/lib/jsdoc/tag/dictionary.js
index 033e6134..18190502 100644
--- a/lib/jsdoc/tag/dictionary.js
+++ b/lib/jsdoc/tag/dictionary.js
@@ -33,13 +33,15 @@ TagDefinition.prototype.synonym = function(synonymName) {
 dictionary = {
     /** @function */
     defineTag: function(title, opts) {
-        _definitions[title] = new TagDefinition(title, opts);
+        var def = new TagDefinition(title, opts);
+        // all the other dictionary functions use normalised names; we should too.
+        _definitions[def.title] = def;
         
         if (opts.isNamespace) {
-            _namespaces.push(title);
+            _namespaces.push(def.title);
         }
         
-        return _definitions[title];
+        return _definitions[def.title];
     },
 
     /** @function */
@@ -55,8 +57,11 @@ dictionary = {
     
     /** @function */
     isNamespace: function(kind) {
-        if ( _namespaces.indexOf(kind) !== -1) {
-            return true;
+        if (kind) {
+            kind = dictionary.normalise(kind);
+            if ( _namespaces.indexOf(kind) !== -1) {
+                return true;
+            }
         }
         
         return false;
diff --git a/test/fixtures/paramtag.js b/test/fixtures/paramtag.js
index db431bfc..c6fd831c 100644
--- a/test/fixtures/paramtag.js
+++ b/test/fixtures/paramtag.js
@@ -39,3 +39,9 @@ function split(delimiter) {
 */
 function commit(atomic) {
 }
+
+/**
+ * @param [async=true] - whether to be asynchronous
+ */
+function request(async) {
+}
diff --git a/test/specs/jsdoc/tag.js b/test/specs/jsdoc/tag.js
index af71b0a0..a324a9c3 100644
--- a/test/specs/jsdoc/tag.js
+++ b/test/specs/jsdoc/tag.js
@@ -1,33 +1,162 @@
 /*global describe: true, env: true, it: true */
 describe("jsdoc/tag", function() {
-    /*jshint evil: true */
-    
-    // TODO: more tests
+    var jsdoc = {
+        tag: require('jsdoc/tag'),
+        dictionary: require('jsdoc/tag/dictionary'),
+        type: require('jsdoc/tag/type')
+    };
 
-    var lenient = !!env.opts.lenient,
-        log = eval(console.log);
-    
-    function badTag() {
-        var Tag = require("jsdoc/tag").Tag;
-        var tag = new Tag("name");
-        return tag;
-    }
-
-    afterEach(function() {
-        env.opts.lenient = lenient;
-        console.log = log;
+    it('should exist', function() {
+        expect(jsdoc.tag).toBeDefined();
+        expect(typeof jsdoc.tag).toBe('object');
     });
 
-    it("throws an exception for bad tags if the lenient option is not enabled", function() {
-        env.opts.lenient = false;
-
-        expect(badTag).toThrow();
+    it('should export a Tag function', function() {
+        expect(jsdoc.tag.Tag).toBeDefined();
+        expect(typeof jsdoc.tag.Tag).toBe('function');
     });
-    
-    it("doesn't throw an exception for bad tags if the lenient option is enabled", function() {
-        console.log = function() {};
-        env.opts.lenient = true;
 
-        expect(badTag).not.toThrow();
+    describe('Tag', function() {
+        var meta = {lineno: 1, filename: 'asdf.js'},
+            desc = 'lalblakd lkjasdlib\n  lija',
+            text = '{!number} [foo=1] - ' + desc,
+            textEg = '<caption>Asdf</caption>\n' +
+                     ' * myFunction(1, 2); // returns 3\n' +
+                     ' * myFunction(3, 4); // returns 7\n';
+        var tagArg = new jsdoc.tag.Tag('arg  ', text, meta), // <-- a symonym of param, space in the title.
+            tagParam = new jsdoc.tag.Tag('param', '[foo=1]', meta), // no type, but has optional and defaultvalue.
+            tagEg  = new jsdoc.tag.Tag('example', textEg, meta), // <-- for keepsWhitespace
+            tagType = new jsdoc.tag.Tag('type', 'MyType ', meta); // <-- for onTagText
+
+        it("should have a 'originalTitle' property, a string", function() {
+            expect(tagArg.originalTitle).toBeDefined();
+            expect(typeof tagArg.originalTitle).toBe('string');
+        });
+
+        it("'originalTitle' property should be the initial tag title, trimmed of whitespace", function() {
+            expect(tagArg.originalTitle).toBe('arg');
+            expect(tagEg.originalTitle).toBe('example');
+        });
+
+        it("should have a 'title' property, a string", function() {
+            expect(tagArg.title).toBeDefined();
+            expect(typeof tagArg.title).toBe('string');
+        });
+
+        it("'title' property should be the normalised tag title", function() {
+            expect(tagArg.title).toBe(jsdoc.dictionary.normalise(tagArg.originalTitle));
+            expect(tagEg.title).toBe(jsdoc.dictionary.normalise(tagEg.originalTitle));
+        });
+
+        it("should have a 'text' property. a string", function () {
+            expect(tagArg.text).toBeDefined();
+            expect(typeof tagArg.text).toBe('string');
+        });
+
+        it("should have a 'value' property", function () {
+            expect(tagArg.value).toBeDefined();
+            expect(tagEg.value).toBeDefined();
+            expect(tagType.value).toBeDefined();
+        });
+
+        describe("'text' property", function() {
+            it("'text' property should be the trimmed tag text, with all leading and trailing space removed unless tagDef.keepsWhitespace", function() {
+                // @example has keepsWhitespace, @param doesn't.
+                // should realy use module:jsdoc/tag~trim here but it's private.
+                expect(tagArg.text).toBe(text.replace(/^\s+|\s+$/g, ''));
+                expect(tagEg.text).toBe(textEg.replace(/^[\n\r\f]+|[\n\r\f]+$/g, ''));
+            });
+
+            it("'text' property should have onTagText run on it if it has it.", function() {
+                var def = jsdoc.dictionary.lookUp('type');
+                expect(def.onTagText).toBeDefined();
+                expect(typeof def.onTagText).toBe('function');
+
+                // @type adds {} around the type if necessary.
+                expect(tagType.text).toBeDefined();
+                expect(tagType.text).toBe(def.onTagText('MyType'));
+            });
+        });
+
+        describe("'value' property", function() {
+            it("'value' property should equal tag text if tagDef.canHaveType and canHaveName are both false", function() {
+                // @example can't have type or name
+                expect(typeof tagEg.value).toBe('string');
+                expect(tagEg.value).toBe(tagEg.text);
+            });
+
+            it("'value' property should be an object if tagDef can have type or name", function () {
+                expect(typeof tagType.value).toBe('object');
+                expect(typeof tagArg.value).toBe('object');
+            });
+
+            function verifyTagType(tag) {
+                var def = jsdoc.dictionary.lookUp(tag.title);
+                expect(def).not.toBe(false);
+                var info = jsdoc.type.parse(tag.text, def.canHaveName, def.canHaveType);
+
+                var props_that_should_be_copied = ['optional', 'nullable', 'variable', 'defaultvalue'];
+                for (var i = 0; i < props_that_should_be_copied.length; ++i) {
+                    var prop = props_that_should_be_copied[i];
+                    if (info.hasOwnProperty(prop)) {
+                        expect(tag.value[prop]).toBe(info[prop]);
+                    }
+                }
+                if (info.type && info.type.length) {
+                    expect(tag.value.type).toBeDefined();
+                    expect(typeof tag.value.type).toBe('object');
+                    expect(tag.value.type.names).toBeDefined();
+                    expect(tag.value.type.names).toEqual(info.type);
+                }
+            }
+            it("if the tag has a type, tag.value should contain the type information", function() {
+                // we assume jsdoc/tag/type.parse works (it has its own tests to verify this);
+                verifyTagType(tagType);
+                verifyTagType(tagArg);
+                verifyTagType(tagParam);
+            });
+
+            it("if the tag has a description beyond the name/type, this should be in tag.value.description", function() {
+                expect(tagType.value.description).not.toBeDefined();
+
+                expect(tagArg.value.description).toBeDefined();
+                expect(tagArg.value.description).toBe(desc);
+            });
+
+            it("if the tag can have a name, it should be stored in tag.value.name", function() {
+                expect(tagArg.value.name).toBeDefined();
+                expect(tagArg.value.name).toBe('foo');
+
+                expect(tagType.value.name).not.toBeDefined();
+            });
+        });
+
+        // further tests for this sort of thing are in jsdoc/tag/validator.js tests.
+        describe("tag validating", function() {
+            /*jshint evil: true */
+            var lenient = !!env.opts.lenient;
+            
+            function badTag() {
+                var tag = new jsdoc.tag.Tag("name");
+                return tag;
+            }
+
+            afterEach(function() {
+                env.opts.lenient = lenient;
+            });
+
+            it("throws an exception for bad tags if the lenient option is not enabled", function() {
+                env.opts.lenient = false;
+
+                expect(badTag).toThrow();
+            });
+            
+            it("doesn't throw an exception for bad tags if the lenient option is enabled", function() {
+                spyOn(console, 'log');
+                env.opts.lenient = true;
+
+                expect(badTag).not.toThrow();
+            });
+        });
     });
-});
\ No newline at end of file
+});
diff --git a/test/specs/jsdoc/tag/dictionary.js b/test/specs/jsdoc/tag/dictionary.js
index af8f72d0..b6e0544c 100644
--- a/test/specs/jsdoc/tag/dictionary.js
+++ b/test/specs/jsdoc/tag/dictionary.js
@@ -1,3 +1,98 @@
-describe("jsdoc/tag/dictionary", function() {
-    //TODO
-});
\ No newline at end of file
+describe('jsdoc/tag/dictionary', function() {
+    var dictionary = require('jsdoc/tag/dictionary');
+
+    it('should exist', function() {
+        expect(dictionary).toBeDefined();
+        expect(typeof dictionary).toBe('object');
+    });
+
+    it('should export a defineTag function', function() {
+        expect(dictionary.defineTag).toBeDefined();
+        expect(typeof dictionary.defineTag).toBe('function');
+    });
+
+    it('should export a lookUp function', function() {
+        expect(dictionary.lookUp).toBeDefined();
+        expect(typeof dictionary.lookUp).toBe('function');
+    });
+
+    it('should export a isNamespace function', function() {
+        expect(dictionary.isNamespace).toBeDefined();
+        expect(typeof dictionary.isNamespace).toBe('function');
+    });
+
+    it('should export a normalise function', function() {
+        expect(dictionary.normalise).toBeDefined();
+        expect(typeof dictionary.normalise).toBe('function');
+    });
+
+    // TODO: should really remove this tag from the dictionary after, but how?
+    var tagOptions = {
+        canHaveValue: true,
+        isNamespace: true
+    },
+        tagTitle = 'testTag',
+        tagSynonym = 'testTag2';
+    var def = dictionary.defineTag(tagTitle, tagOptions).synonym(tagSynonym);
+    // Should really test TagDefinition but they are private.
+    // Instead, we'll just tests all the properties we expect of it.
+    describe("defineTag", function() {
+
+        // Since TagDefinition is private, I'll just test for its properties here.
+        it("returns an object with 'title' property", function() {
+            expect(typeof def).toBe('object');
+            // how to test?
+            expect(def.title).toBeDefined();
+            expect(typeof def.title).toBe('string');
+            expect(def.title).toBe(dictionary.normalise(tagTitle));
+        });
+
+        it("returned object has all the tag properties copied over", function() {
+            for (var prop in tagOptions) {
+                if (tagOptions.hasOwnProperty(prop)) {
+                    expect(def[prop]).toBe(tagOptions[prop]);
+                }
+            }
+        });
+    });
+
+    describe("lookUp", function() {
+        it("retrieves definition when using the tag's canonical name", function() {
+            expect(dictionary.lookUp(tagTitle)).toBe(def);
+        });
+
+        it("retrieves definition when using a synonym", function() {
+            expect(dictionary.lookUp(tagSynonym)).toBe(def);
+        });
+
+        it("returns FALSE when a tag is not found", function() {
+            expect(dictionary.lookUp('lkjas1l24jk')).toBe(false);
+        });
+    });
+
+    describe("isNamespace", function() {
+        it("returns whether a tag is a namespace when using its canonical name", function() {
+            expect(dictionary.isNamespace(tagTitle)).toBe(true);
+        });
+
+        it("returns whether a tag is a namespace when using its synonym", function() {
+            expect(dictionary.isNamespace(tagSynonym)).toBe(true);
+        });
+
+        it("non-existent tags or non-namespace tags should return false", function() {
+            expect(dictionary.isNamespace('see')).toBe(false);
+            expect(dictionary.isNamespace('lkjasd90034')).toBe(false);
+        });
+    });
+
+    describe("normalise", function() {
+        it("should return the tag's title if it is not a synonym", function() {
+            expect(dictionary.normalise('FooBar')).toBe('foobar');
+            expect(dictionary.normalise(tagTitle)).toBe(def.title);
+        });
+
+        it("should return the canonical name of a tag if the synonym is normalised", function() {
+            expect(dictionary.normalise(tagSynonym)).toBe(def.title);
+        });
+    });
+});
diff --git a/test/specs/jsdoc/tag/dictionary/definitions.js b/test/specs/jsdoc/tag/dictionary/definitions.js
new file mode 100644
index 00000000..4abae895
--- /dev/null
+++ b/test/specs/jsdoc/tag/dictionary/definitions.js
@@ -0,0 +1,15 @@
+describe('jsdoc/tag/dictionary/definitions', function() {
+    var type = require('jsdoc/tag/dictionary/definitions');
+
+    it('should exist', function() {
+        expect(type).toBeDefined();
+        expect(typeof type).toBe('object');
+    });
+    
+    it('should export a defineTags function', function() {
+        expect(type.defineTags).toBeDefined();
+        expect(typeof type.defineTags).toBe('function');
+    });
+    // whole bit of dictionary.defineTags...but it just calls dictionary.defineTag
+    // and if I validate that then the rest is automatically validated?
+});
diff --git a/test/specs/jsdoc/tag/type.js b/test/specs/jsdoc/tag/type.js
index a5ed0830..bec572f8 100644
--- a/test/specs/jsdoc/tag/type.js
+++ b/test/specs/jsdoc/tag/type.js
@@ -92,6 +92,10 @@ describe('jsdoc/tag/type', function() {
             desc = '{string=} [foo]';
             info = jsdoc.tag.type.parse(desc, true, true);
             expect(info.optional).toBe(true);
+
+            desc = '[foo]';
+            info = jsdoc.tag.type.parse(desc, true, true);
+            expect(info.optional).toBe(true);
         });
         
         it('should return the types as an array', function() {
diff --git a/test/specs/jsdoc/tag/validator.js b/test/specs/jsdoc/tag/validator.js
index 4dd4be63..56070edb 100644
--- a/test/specs/jsdoc/tag/validator.js
+++ b/test/specs/jsdoc/tag/validator.js
@@ -1,3 +1,94 @@
-describe("jsdoc/tag/validator", function() {
-    //TODO
-});
\ No newline at end of file
+describe('jsdoc/tag/validator', function() {
+    var validator = require('jsdoc/tag/validator'),
+        tag = require('jsdoc/tag');
+
+    it('should exist', function() {
+        expect(validator).toBeDefined();
+        expect(typeof validator).toBe('object');
+    });
+
+    it('should export a validate function', function() {
+        expect(validator.validate).toBeDefined();
+        expect(typeof validator.validate).toBe('function');
+    });
+
+    // Note: various Error classes are private so we just test whether *any*
+    // error was thrown, not against particular types (e.g. UnknownTagError).
+    describe('validate', function() {
+        var lenient = !!env.opts.lenient,
+            allowUnknown = !!env.conf.tags.allowUnknownTags,
+            badTag = {title: 'lkjasdlkjfb'},
+            meta = {filename: 'asdf.js', lineno: 1},
+            goodTag = new tag.Tag('name', 'MyDocletName', meta), // mustHaveValue
+            goodTag2 = new tag.Tag('ignore', '', meta); // mustNotHaveValue
+       
+        function validateTag(tag) {
+           return function() { validator.validate(tag, meta); };
+        } 
+
+        beforeEach(function() {
+            spyOn(console, 'log');
+        });
+
+        afterEach(function() {
+            env.opts.lenient = lenient;
+            env.conf.tags.allowUnknownTags = allowUnknown;
+        });
+
+        it("throws an error if the tag is not in the dictionary, conf.tags.allowUnknownTags is false and lenient is false", function() {
+            env.opts.lenient = false;
+            env.conf.tags.allowUnknownTags = false;
+            expect(validateTag(badTag)).toThrow();
+        });
+
+        it("throws NO error if the tag is not in the dictionary, conf.tags.allowUnknownTags is false and lenient is true", function() {
+            env.opts.lenient = true;
+            env.conf.tags.allowUnknownTags = false;
+            expect(validateTag(badTag)).not.toThrow();
+        });
+
+        it("doesn't throw an error if the tag is not in the dictionary and conf.tags.allowUnknownTags is true, regardless of lenience", function() {
+            // if it doesn't throw an error with lenient false, then it won't throw it with lenient true (we have
+            // tested lenient already in util/error.js)
+            env.opts.lenient = false;
+            env.conf.tags.allowUnknownTags = true;
+            expect(validateTag(badTag)).not.toThrow();
+        });
+
+        it("throws no error for valid tags", function() {
+            env.opts.lenient = false;
+            expect(validateTag(goodTag)).not.toThrow();
+            expect(validateTag(goodTag2)).not.toThrow();
+        });
+
+        it("throws an error if the tag has no text but .mustHaveValue is true and lenient is false, or none if it's true", function() {
+            // the name tag has .mustHaveValue.
+            var oldText = goodTag.text;
+            delete goodTag.text;
+
+            env.opts.lenient = false;
+            expect(validateTag(goodTag)).toThrow();
+
+            env.opts.lenient = true;
+            expect(validateTag(goodTag)).not.toThrow();
+
+            goodTag.text = oldText;
+        });
+
+        it("throws an error if the tag has text but .mustNotHaveValue is true and lenient is false, or none if it's true", function() {
+            var oldVal = goodTag2.mustNotHaveValue,
+                text = goodTag2.text;
+            goodTag2.mustNotHaveValue = true;
+            goodTag2.text = goodTag2.text || 'asdf';
+
+            env.opts.lenient = false;
+            expect(validateTag(goodTag2)).toThrow();
+
+            env.opts.lenient = true;
+            expect(validateTag(goodTag2)).not.toThrow();
+
+            goodTag2.mustNotHaveValue = oldVal;
+            goodTag2.text = oldVal;
+        });
+    });
+});
diff --git a/test/specs/tags/paramtag.js b/test/specs/tags/paramtag.js
index 10e847fa..7145c83f 100644
--- a/test/specs/tags/paramtag.js
+++ b/test/specs/tags/paramtag.js
@@ -6,7 +6,8 @@ describe("@param tag", function() {
         getElement = docSet.getByLongname('getElement')[0],
         combine = docSet.getByLongname('combine')[0],
         split = docSet.getByLongname('split')[0],
-        commit = docSet.getByLongname('commit')[0];
+        commit = docSet.getByLongname('commit')[0],
+        request = docSet.getByLongname('request')[0];
 
     it('When a symbol has an @param tag with a type before the name, the doclet has a params property that includes that param.', function() {
         expect(typeof find.params).toBe('object');
@@ -62,7 +63,18 @@ describe("@param tag", function() {
         expect(commit.params[0].description).toBe('If true make the commit atomic.');
     });
 
+    it('When a symbol has a @param tag with no type but a name that indicates a default value or optional type, this is copied over to the params property.', function() {
+        expect(typeof request.params).toBe('object');
+        expect(request.params.length).toBe(1);
+        expect(request.params[0].type).toBeUndefined();
+        expect(request.params[0].name).toBe('async');
+        expect(request.params[0].defaultvalue).toBe('true');
+        expect(request.params[0].optional).toBe(true);
+        expect(request.params[0].description).toBe('whether to be asynchronous');
+    });
+
     it('When a symbol has an @param tag with no name and a name is given in the code, the doclet has a params property that includes that param with the name from the code.', function() {
         expect(commit.params[0].name).toBe('atomic');
     });
-});
\ No newline at end of file
+
+});