Add test to check for valid schema

This is the beginning of a suite of tests for schema correctness.

src/juxt/jsonschema/core.clj

@@ -0,0 +1,10 @@
+(ns juxt.jsonschema.core)
+
+(defn array? [x]
+  (sequential? x))
+
+(defn object? [x]
+  (map? x))
+
+(defn schema? [x]
+  (or (object? x) (boolean? x)))

src/juxt/jsonschema/schema.clj

@@ -2,6 +2,7 @@
 
 (ns juxt.jsonschema.schema
   (:require
+   [juxt.jsonschema.core :refer [array? object? schema?]]
    [lambdaisland.uri :refer [join]]))
 
 (defn- with-base-uri-meta
@@ -35,7 +36,25 @@
     (vector? schema)
     (mapcat index-by-uri schema)))
 
+(defmulti validate-keyword (fn [kw v] kw))
+
+(defmethod validate-keyword :default [kw v] nil)
+
+(defmethod validate-keyword "type" [kw v]
+  (when-not (or (string? v) (array? v))
+    (throw (ex-info "The value of 'type' MUST be either a string or an array" {}))))
+
+(defn- validate [schema]
+  (or
+   (boolean? schema)
+   (nil? schema)
+   (doseq [[k v] (seq schema)]
+     (validate-keyword k v))))
+
 (defn schema [schema]
+  ;; TODO: Ensure schema is returned as-is if it's existing schema
+  ;; TODO: Add ^:juxt/schema true - which is the right keyword here?
+  (validate schema)
   (let [schema (with-base-uri-meta schema)
         index (into {} (index-by-uri schema))]
     (cond->

src/juxt/jsonschema/validate.cljc

@@ -9,22 +9,14 @@
    [clojure.java.io :as io] ;; TODO: Support cljs
    [clojure.test :refer [deftest is are]]
    [juxt.jsonschema.jsonpointer :as jsonpointer]
+   [juxt.jsonschema.core :refer [array? object? schema?]]
    [juxt.jsonschema.schema :as schema]
    [juxt.jsonschema.resolve :as resolv]
    [juxt.jsonschema.regex :as regex]
    [lambdaisland.uri :as uri]))
 
 (declare validate*)
 
-(defn array? [x]
-  (sequential? x))
-
-(defn object? [x]
-  (map? x))
-
-(defn schema? [x]
-  (or (object? x) (boolean? x)))
-
 ;; All references here relate to
 ;; draft-handrews-json-schema-validation-01.txt unless otherwise
 ;; stated.
@@ -451,7 +443,8 @@
                    :causes (:errors result)}})))))
 
 ;; TODO: Rather than get, use a macro to retrieve either strings and
-;; keywords, supporting both
+;; keywords, supporting both. But BE CAREFUL with :default as we'll
+;; need to repoint the defmulti's :default in that case.
 
 (defmulti check-format (fn [fmt instance ctx] fmt))
 

test/juxt/jsonschema/schema_test.clj

@@ -0,0 +1,14 @@
+(ns juxt.jsonschema.schema-test
+  (:require
+   [juxt.jsonschema.schema :refer [schema]]
+   [clojure.test :refer [deftest is are testing]]
+   [juxt.jsonschema.schema :as schema])
+  (:import
+   (clojure.lang ExceptionInfo)))
+
+(deftest schema-test
+  (testing "bad types"
+    (is
+     (thrown?
+      ExceptionInfo
+      (schema {"type" 10})))))