diff --git a/lib/api/test/integration/validateMessage.test.js b/lib/api/test/integration/validateMessage.test.js
index d71bef8b..bb01a895 100644
--- a/lib/api/test/integration/validateMessage.test.js
+++ b/lib/api/test/integration/validateMessage.test.js
@@ -90,15 +90,16 @@ describe('validateMessage', () => {
     });
 
     describe('method', () => {
+      // See https://github.com/apiaryio/gavel.js/issues/158
       it.skip('compares methods');
     });
 
-    describe.skip('headers', () => {
-      it('has no validator set', () => {
-        assert.propertyVal(result.headers, 'validator', null);
+    describe('headers', () => {
+      it('has "HeadersJsonExample" validator', () => {
+        assert.propertyVal(result.headers, 'validator', 'HeadersJsonExample');
       });
 
-      it('has "application/vnd.apiary.http-headers+json" as real headers type', () => {
+      it('has "application/vnd.apiary.http-headers+json" as real type', () => {
         assert.propertyVal(
           result.headers,
           'realType',
@@ -106,31 +107,37 @@ describe('validateMessage', () => {
         );
       });
 
-      it('has no expected headers type', () => {
-        assert.propertyVal(result.headers, 'expectedType', null);
+      it('has "application/vnd.apiary.http-headers+json" expcted type', () => {
+        assert.propertyVal(
+          result.headers,
+          'expectedType',
+          'application/vnd.apiary.http-headers+json'
+        );
       });
 
-      describe('produces an error', () => {
-        it('exactly one error', () => {
-          assert.lengthOf(result.headers.results, 1);
-        });
-
-        it('has "error" severity', () => {
-          assert.propertyVal(result.headers.results[0], 'severity', 'error');
-        });
-
-        it('has explanatory message', () => {
-          assert.propertyVal(
-            result.headers.results[0],
-            'message',
-            `\
-No validator found for real data media type
-"application/vnd.apiary.http-headers+json"
-and expected data media type
-"null".`
-          );
-        });
+      it('has no errors', () => {
+        assert.lengthOf(result.headers.results, 0);
       });
+
+      //       describe('produces an error', () => {
+      //         it('exactly one error', () => {});
+
+      //         it('has "error" severity', () => {
+      //           assert.propertyVal(result.headers.results[0], 'severity', 'error');
+      //         });
+
+      //         it('has explanatory message', () => {
+      //           assert.propertyVal(
+      //             result.headers.results[0],
+      //             'message',
+      //             `\
+      // No validator found for real data media type
+      // "application/vnd.apiary.http-headers+json"
+      // and expected data media type
+      // "null".`
+      //           );
+      //         });
+      //       });
     });
 
     describe('body', () => {
diff --git a/lib/api/test/unit/units/validateBody.test.js b/lib/api/test/unit/units/validateBody.test.js
index 9b8b7518..6f6346b9 100644
--- a/lib/api/test/unit/units/validateBody.test.js
+++ b/lib/api/test/unit/units/validateBody.test.js
@@ -12,14 +12,14 @@ describe('validateBody', () => {
     ];
 
     scenarios.forEach(({ name, value }) => {
-      it(`errors when given ${name}`, () => {
+      it(`throws when given ${name}`, () => {
         assert.throw(() => validateBody({ body: value }, { body: value }));
       });
     });
   });
 
   describe('when given supported body type', () => {
-    describe('with explicit Content-Type header', () => {
+    describe('with explicit "Content-Type" header', () => {
       describe('application/json', () => {
         describe('with matching body type', () => {
           const res = validateBody(
@@ -27,19 +27,21 @@ describe('validateBody', () => {
               body: '{ "foo": "bar" }',
               headers: { 'content-type': 'application/json' }
             },
-            { body: '{ "foo": "bar" }' }
+            {
+              body: '{ "foo": "bar" }'
+            }
           );
 
-          it('has application/json real type', () => {
-            assert.propertyVal(res, 'realType', 'application/json');
+          it('has "JsonExample" validator', () => {
+            assert.propertyVal(res, 'validator', 'JsonExample');
           });
 
-          it('has application/json expected type', () => {
-            assert.propertyVal(res, 'expectedType', 'application/json');
+          it('has "application/json" real type', () => {
+            assert.propertyVal(res, 'realType', 'application/json');
           });
 
-          it('has JsonExample validator', () => {
-            assert.propertyVal(res, 'validator', 'JsonExample');
+          it('has "application/json" expected type', () => {
+            assert.propertyVal(res, 'expectedType', 'application/json');
           });
 
           it('has no errors', () => {
@@ -56,16 +58,20 @@ describe('validateBody', () => {
             { body: '{ "foo": "bar" }' }
           );
 
-          it('fallbacks to text/plain real type', () => {
+          it('has no validator', () => {
+            assert.propertyVal(res, 'validator', null);
+          });
+
+          it('fallbacks to "text/plain" real type', () => {
             assert.propertyVal(res, 'realType', 'text/plain');
           });
 
-          it('has application/json expected type', () => {
+          it('has "application/json" expected type', () => {
             assert.propertyVal(res, 'expectedType', 'application/json');
           });
 
           describe('produces content-type error', () => {
-            it('has proper severity', () => {
+            it('has "error" severity', () => {
               assert.propertyVal(res.results[0], 'severity', 'error');
             });
 
@@ -76,10 +82,6 @@ describe('validateBody', () => {
               );
             });
           });
-
-          it('has no validator', () => {
-            assert.propertyVal(res, 'validator', null);
-          });
         });
       });
 
@@ -97,16 +99,16 @@ describe('validateBody', () => {
             }
           );
 
-          it('has application/hal+json real type', () => {
-            assert.propertyVal(res, 'realType', 'application/hal+json');
+          it('has "JsonExample" validator', () => {
+            assert.propertyVal(res, 'validator', 'JsonExample');
           });
 
-          it('has application/json expected type', () => {
-            assert.propertyVal(res, 'expectedType', 'application/json');
+          it('has "application/hal+json" real type', () => {
+            assert.propertyVal(res, 'realType', 'application/hal+json');
           });
 
-          it('has JsonExample validator', () => {
-            assert.propertyVal(res, 'validator', 'JsonExample');
+          it('has "application/json" expected type', () => {
+            assert.propertyVal(res, 'expectedType', 'application/json');
           });
 
           it('has no errors', () => {
@@ -127,11 +129,15 @@ describe('validateBody', () => {
             }
           );
 
-          it('fallbacks to text/plain real type', () => {
+          it('has no validator', () => {
+            assert.propertyVal(res, 'validator', null);
+          });
+
+          it('fallbacks to "text/plain" real type', () => {
             assert.propertyVal(res, 'realType', 'text/plain');
           });
 
-          it('has text/plain expected type', () => {
+          it('has "text/plain" expected type', () => {
             assert.propertyVal(res, 'expectedType', 'text/plain');
           });
 
@@ -139,6 +145,7 @@ describe('validateBody', () => {
             it('has "error" severity', () => {
               assert.propertyVal(res.results[0], 'severity', 'error');
             });
+
             it('has explanatory message', () => {
               assert.match(
                 res.results[0].message,
@@ -146,31 +153,27 @@ describe('validateBody', () => {
               );
             });
           });
-
-          it('has no validator', () => {
-            assert.propertyVal(res, 'validator', null);
-          });
         });
       });
     });
 
-    describe('without explicit Content-Type header', () => {
+    describe('without explicit "Content-Type" header', () => {
       describe('text/plain', () => {
         describe('with matching bodies', () => {
           const res = validateBody({ body: 'foo' }, { body: 'foo' });
 
+          it('has "TextDiff" validator', () => {
+            assert.propertyVal(res, 'validator', 'TextDiff');
+          });
+
           it('has text/plain real type', () => {
             assert.propertyVal(res, 'realType', 'text/plain');
           });
 
-          it('has text/plain expected type', () => {
+          it('has "text/plain" expected type', () => {
             assert.propertyVal(res, 'expectedType', 'text/plain');
           });
 
-          it('has TextDiff validator', () => {
-            assert.propertyVal(res, 'validator', 'TextDiff');
-          });
-
           it('has no errors', () => {
             assert.lengthOf(res.results, 0);
           });
@@ -179,16 +182,16 @@ describe('validateBody', () => {
         describe('with non-matching bodies', () => {
           const res = validateBody({ body: 'foo ' }, { body: 'bar' });
 
-          it('has text/plain real type', () => {
-            assert.propertyVal(res, 'realType', 'text/plain');
+          it('has "TextDiff" validator', () => {
+            assert.propertyVal(res, 'validator', 'TextDiff');
           });
 
-          it('has text/plain expected type', () => {
-            assert.propertyVal(res, 'expectedType', 'text/plain');
+          it('has "text/plain" real type', () => {
+            assert.propertyVal(res, 'realType', 'text/plain');
           });
 
-          it('has TextDiff validator', () => {
-            assert.propertyVal(res, 'validator', 'TextDiff');
+          it('has "text/plain" expected type', () => {
+            assert.propertyVal(res, 'expectedType', 'text/plain');
           });
 
           describe('produces validation error', () => {
@@ -219,16 +222,16 @@ describe('validateBody', () => {
             { body: '{ "foo": "bar" }' }
           );
 
-          it('has application/json real type', () => {
-            assert.propertyVal(res, 'realType', 'application/json');
+          it('has "JsonExample" validator', () => {
+            assert.propertyVal(res, 'validator', 'JsonExample');
           });
 
-          it('has application/json expected type', () => {
-            assert.propertyVal(res, 'expectedType', 'application/json');
+          it('has "application/json" real type', () => {
+            assert.propertyVal(res, 'realType', 'application/json');
           });
 
-          it('has JsonExample validator', () => {
-            assert.propertyVal(res, 'validator', 'JsonExample');
+          it('has "application/json" expected type', () => {
+            assert.propertyVal(res, 'expectedType', 'application/json');
           });
 
           it('has no errors', () => {
@@ -242,16 +245,16 @@ describe('validateBody', () => {
             { body: '{ "bar": null }' }
           );
 
-          it('has application/json real type', () => {
-            assert.propertyVal(res, 'realType', 'application/json');
+          it('has "JsonExample" validator', () => {
+            assert.propertyVal(res, 'validator', 'JsonExample');
           });
 
-          it('has application/json expected type', () => {
-            assert.propertyVal(res, 'expectedType', 'application/json');
+          it('has "application/json" real type', () => {
+            assert.propertyVal(res, 'realType', 'application/json');
           });
 
-          it('has JsonExample validator', () => {
-            assert.propertyVal(res, 'validator', 'JsonExample');
+          it('has "application/json" expected type', () => {
+            assert.propertyVal(res, 'expectedType', 'application/json');
           });
 
           describe('produces validation errors', () => {
diff --git a/lib/api/test/unit/units/validateBody/getBodySchemaType.test.js b/lib/api/test/unit/units/validateBody/getBodySchemaType.test.js
index edd400db..adc102e2 100644
--- a/lib/api/test/unit/units/validateBody/getBodySchemaType.test.js
+++ b/lib/api/test/unit/units/validateBody/getBodySchemaType.test.js
@@ -4,45 +4,68 @@ const { getBodySchemaType } = require('../../../../units/validateBody');
 
 describe('getBodySchemaType', () => {
   describe('when given non-string schema', () => {
-    // ...
-  });
+    const values = [
+      ['number', 123],
+      ['object', { foo: 'bar' }],
+      ['array', [1, 2, 3]],
+      ['null', null],
+      ['undefined', undefined]
+    ];
 
-  describe('when given json schema', () => {
-    describe('that contains object', () => {
-      const res = getBodySchemaType('{ "foo": "bar" }');
+    values.forEach(([name, value]) => {
+      describe(`which is ${name}`, () => {
+        const [error, mediaType] = getBodySchemaType(value);
 
-      it('returns no errors', () => {
-        assert.isNull(res[0]);
-      });
+        it('returns "application/schema+json" media type', () => {
+          assert.deepEqual(
+            mediaType,
+            mediaTyper.parse('application/schema+json')
+          );
+        });
 
-      it('returns "application/schema+json" media type', () => {
-        assert.deepEqual(res[1], mediaTyper.parse('application/schema+json'));
+        it('has no errors', () => {
+          assert.isNull(error);
+        });
       });
     });
+  });
 
-    describe('that contains array', () => {
-      const res = getBodySchemaType('[1, 2, 3]');
+  describe('when given JSON', () => {
+    const jsonSchemas = [
+      ['object', '{ "foo": "bar" }'],
+      ['array', '[1, 2, 3]']
+    ];
 
-      it('returns no errors', () => {
-        assert.isNull(res[0]);
-      });
+    jsonSchemas.forEach(([name, jsonSchema]) => {
+      describe(`that contains ${name}`, () => {
+        const [error, mediaType] = getBodySchemaType(jsonSchema);
 
-      it('returns "application/schema+json" media type', () => {
-        assert.deepEqual(res[1], mediaTyper.parse('application/schema+json'));
+        it('returns "application/schema+json" media type', () => {
+          assert.deepEqual(
+            mediaType,
+            mediaTyper.parse('application/schema+json')
+          );
+        });
+
+        it('returns no errors', () => {
+          assert.isNull(error);
+        });
       });
     });
   });
 
-  describe('when given non-json schema', () => {
-    const res = getBodySchemaType('foo');
+  describe('when given non-JSON string', () => {
+    const [error, mediaType] = getBodySchemaType('foo');
+
+    it('returns no media type', () => {
+      assert.isNull(mediaType);
+    });
 
     it('returns parsing error', () => {
       assert.match(
-        res[0],
+        error,
         /^Can't validate: expected body JSON Schema is not a parseable JSON:/
       );
     });
-
-    it('returns no media type', () => [assert.isNull(res[1])]);
   });
 });
diff --git a/lib/api/test/unit/units/validateBody/getBodyType.test.js b/lib/api/test/unit/units/validateBody/getBodyType.test.js
index 4d58786a..d9ba8dd3 100644
--- a/lib/api/test/unit/units/validateBody/getBodyType.test.js
+++ b/lib/api/test/unit/units/validateBody/getBodyType.test.js
@@ -6,10 +6,10 @@ const jsonTypes = ['application/json', 'application/schema+json'];
 const nonJsonTypes = ['text/plain'];
 
 describe('getBodyType', () => {
-  describe('when given json-like content type', () => {
+  describe('when given JSON-like content type', () => {
     jsonTypes.forEach((jsonType) => {
       describe(`when given "${jsonType}" content type`, () => {
-        describe('and parsable json body', () => {
+        describe('and parsable JSON body', () => {
           const res = getBodyType('{ "foo": "bar" }', jsonType, 'real');
 
           it('returns no errors', () => {
@@ -21,7 +21,7 @@ describe('getBodyType', () => {
           });
         });
 
-        describe('and non-parsable json body', () => {
+        describe('and non-parsable JSON body', () => {
           const res = getBodyType('abc', jsonType, 'real');
 
           it('returns parsing error', () => {
@@ -46,7 +46,7 @@ describe('getBodyType', () => {
     });
   });
 
-  describe('when given non-json content type', () => {
+  describe('when given non-JSON content type', () => {
     nonJsonTypes.forEach((nonJsonType) => {
       describe(`when given "${nonJsonType}" content type`, () => {
         describe('and parsable json body', () => {
@@ -61,7 +61,7 @@ describe('getBodyType', () => {
           });
         });
 
-        describe('and a non-json body', () => {
+        describe('and a non-JSON body', () => {
           const res = getBodyType('abc', nonJsonType, 'real');
 
           it('returns no errors', () => {
diff --git a/lib/api/test/unit/units/validateBody/getBodyValidator.test.js b/lib/api/test/unit/units/validateBody/getBodyValidator.test.js
index 9e0bfa57..16bf3d2e 100644
--- a/lib/api/test/unit/units/validateBody/getBodyValidator.test.js
+++ b/lib/api/test/unit/units/validateBody/getBodyValidator.test.js
@@ -43,4 +43,24 @@ describe('getBodyValidator', () => {
       });
     });
   });
+
+  // describe('when given unknown media type', () => {
+  //   const unknownContentTypes = [['text/html', 'text/xml']];
+
+  //   unknownContentTypes.forEach((contentTypes) => {
+  //     const [realContentType, expectedContentType] = contentTypes;
+  //     const [real, expected] = getMediaTypes(
+  //       realContentType,
+  //       expectedContentType
+  //     );
+
+  //     describe(`${realContentType} + ${expectedContentType}`, () => {
+  //       const [error, validator] = getBodyValidator(real, expected);
+
+  //       it('...', () => {
+  //         console.log({ error, validator });
+  //       });
+  //     });
+  //   });
+  // });
 });
diff --git a/lib/api/test/unit/units/validateBody/isJson.test.js b/lib/api/test/unit/units/validateBody/isJson.test.js
index 38519801..54ec2008 100644
--- a/lib/api/test/unit/units/validateBody/isJson.test.js
+++ b/lib/api/test/unit/units/validateBody/isJson.test.js
@@ -4,17 +4,17 @@ const { isJson } = require('../../../../units/validateBody');
 
 describe('isJson', () => {
   describe('returns true', () => {
-    it('when given valid json media type', () => {
+    it('when given valid JSON media type', () => {
       assert.isTrue(isJson(mediaTyper.parse('application/json')));
     });
 
-    it('when given json-compatible media type', () => {
+    it('when given JSON-compatible media type', () => {
       assert.isTrue(isJson(mediaTyper.parse('application/schema+json')));
     });
   });
 
   describe('returns false', () => {
-    it('when given non-json media type', () => {
+    it('when given non-JSON media type', () => {
       assert.isFalse(isJson(mediaTyper.parse('text/plain')));
     });
 
diff --git a/lib/api/test/unit/units/validateBody/isJsonSchema.test.js b/lib/api/test/unit/units/validateBody/isJsonSchema.test.js
index a2a4bb15..09f8ff86 100644
--- a/lib/api/test/unit/units/validateBody/isJsonSchema.test.js
+++ b/lib/api/test/unit/units/validateBody/isJsonSchema.test.js
@@ -4,7 +4,7 @@ const { isJsonSchema } = require('../../../../units/validateBody');
 
 describe('isJsonSchema', () => {
   describe('returns true', () => {
-    it('when given a json schema media type', () => {
+    it('when given a JSON schema media type', () => {
       assert.isTrue(isJsonSchema(mediaTyper.parse('application/schema+json')));
     });
   });
diff --git a/lib/api/test/unit/units/validateStatusCode.test.js b/lib/api/test/unit/units/validateStatusCode.test.js
index e22cfbbe..2c9592ef 100644
--- a/lib/api/test/unit/units/validateStatusCode.test.js
+++ b/lib/api/test/unit/units/validateStatusCode.test.js
@@ -12,15 +12,15 @@ describe('validateStatusCode', () => {
       }
     );
 
-    it('has proper validator', () => {
+    it('has "TextDiff" validator', () => {
       assert.propertyVal(res, 'validator', 'TextDiff');
     });
 
-    it('has proper expected type', () => {
+    it('has "text/vnd.apiary.status-code" expected type', () => {
       assert.propertyVal(res, 'expectedType', 'text/vnd.apiary.status-code');
     });
 
-    it('has proper real type', () => {
+    it('has "text/vnd.apiary.status-code" real type', () => {
       assert.propertyVal(res, 'realType', 'text/vnd.apiary.status-code');
     });
 
@@ -39,25 +39,34 @@ describe('validateStatusCode', () => {
       }
     );
 
-    it('has proper validator', () => {
+    it('has "TextDiff" validator', () => {
       assert.propertyVal(res, 'validator', 'TextDiff');
     });
 
-    it('has proper expected type', () => {
+    it('has "text/vnd.apiary.status-code" expected type', () => {
       assert.propertyVal(res, 'expectedType', 'text/vnd.apiary.status-code');
     });
 
-    it('has proper real type', () => {
+    it('has "text/vnd.apiary.status-code" real type', () => {
       assert.propertyVal(res, 'realType', 'text/vnd.apiary.status-code');
     });
 
-    it('has errors', () => {
-      assert.deepPropertyVal(res, 'results', [
-        {
-          message: 'Real and expected data does not match.',
-          severity: 'error'
-        }
-      ]);
+    describe('produces error', () => {
+      it('exactly one error', () => {
+        assert.lengthOf(res.results, 1);
+      });
+
+      it('has "error" severity', () => {
+        assert.propertyVal(res.results[0], 'severity', 'error');
+      });
+
+      it('has explanatory message', () => {
+        assert.propertyVal(
+          res.results[0],
+          'message',
+          'Real and expected data does not match.'
+        );
+      });
     });
   });
 });