Track initial set of LawError subtypes, tests

lib/errors.coffee

@@ -0,0 +1,48 @@
+error = require 'tea-error'
+
+# Create a constructor for better errors
+LawError = error 'LawError'
+
+# subtypes = [
+#   'FailedArgumentLookup'
+#   'MissingArgument'
+#   'InvalidArgument'
+# ]
+#
+
+# Lots of copy-paste code, obvious shared structure in the class
+# definitions below. Can this be factored out in a CS-idiomatic way?
+
+class FailedArgumentLookupError extends LawError
+  name: 'LawError/FailedArgumentLookup'
+
+  constructor: (message, properties, callee) ->
+    message = message or "Unspecified #{@name}"
+
+    super message, properties, callee
+
+
+class MissingArgumentError extends LawError
+  name: 'LawError/MissingArgument'
+
+  constructor: (message, properties, callee) ->
+    message = message or "Unspecified #{@name}"
+
+    super message, properties, callee
+
+
+class InvalidArgumentError extends LawError
+  name: 'LawError/InvalidArgument'
+
+  constructor: (message, properties, callee) ->
+    message = message or "Unspecified #{@name}"
+
+    super message, properties, callee
+
+
+module.exports = {
+  LawError
+  FailedArgumentLookupError
+  MissingArgumentError
+  InvalidArgumentError
+}

package.json

@@ -8,7 +8,8 @@
   "main":"./index.js",
 
   "dependencies":{
-    "coffee-script":"*"
+    "coffee-script":"*",
+    "tea-error":"*"
   },
   "devDependencies":{
     "mocha":"*",

test/errors.coffee

@@ -0,0 +1,111 @@
+should = require 'should'
+
+{
+  LawError
+  FailedArgumentLookupError
+  MissingArgumentError
+  InvalidArgumentError
+} = require '../lib/errors'
+
+
+describe 'errors', ->
+  describe 'LawError', ->
+    beforeEach (done) ->
+      @err = new LawError()
+      done()
+
+    it 'should be an instance of Error', (done) ->
+      (@err instanceof Error).should.be.true
+      done()
+
+    it 'should be an instance of LawError', (done) ->
+      (@err instanceof LawError).should.be.true
+      done()
+
+  describe 'FailedArgumentLookupError', ->
+    describe 'an instance without any passed arguments', ->
+      beforeEach (done) ->
+        @err = new FailedArgumentLookupError()
+        done()
+
+      describe 'inheriting from LawError', ->
+        it 'should be an instance of Error', (done) ->
+          (@err instanceof Error).should.be.true
+          done()
+
+        it 'should be an instance of LawError', (done) ->
+          (@err instanceof LawError).should.be.true
+          done()
+
+        it 'should be an instance of FailedArgumentLookupError', (done) ->
+          (@err instanceof FailedArgumentLookupError).should.be.true
+          done()
+
+        it 'should inherit Error, tea-error properties', (done) ->
+          should.exist @err.toJSON
+          should.exist @err.message
+          should.exist @err.stack
+          done()
+
+      it 'should have a reasonable default message', (done) ->
+        expectedMessage = 'Unspecified LawError/FailedArgumentLookup'
+        @err.message.should.equal expectedMessage
+        done()
+
+    describe 'an instance with passed arguments', ->
+      beforeEach (done) ->
+        @message = 'Could not look up required argument `username`'
+        @properties =
+          serviceName: 'doSomething'
+          args:
+            sessionId: 'deadbeef'
+            timestamp: Date.now()
+        @err = new FailedArgumentLookupError @message, @properties
+        done()
+
+      it 'should have a correct, descriptive message', (done) ->
+        should.exist @err.message
+        @err.message.should.equal @message
+        done()
+
+      it 'should have the properties we gave it', (done) ->
+        @err.should.include @properties
+        done()
+
+  describe 'MissingArgumentError', ->
+    beforeEach (done) ->
+      @message = 'Missing required argument `username`'
+      @properties =
+        serviceName: 'doSomething'
+        args:
+          sessionId: 'deadbeef'
+          timestamp: Date.now()
+      @err = new MissingArgumentError @message, @properties
+      done()
+
+    it 'should be an instance of MissingArgumentError', (done) ->
+      (@err instanceof MissingArgumentError).should.be.true
+      done()
+
+    it 'should have a correct, descriptive message', (done) ->
+      @err.message.should.equal @message
+      done()
+
+  describe 'InvalidArgumentError', ->
+    beforeEach (done) ->
+      @message = 'Invalid argument `sessionId`'
+      @properties =
+        serviceName: 'doSomething'
+        args:
+          sessionId: 'malformed'
+          timestamp: Date.now()
+      @err = new InvalidArgumentError @message, @properties
+      done()
+
+    it 'should be an instance of InvalidArgumentError', (done) ->
+      (@err instanceof InvalidArgumentError).should.be.true
+      done()
+
+    it 'should have a correct, descriptive message', (done) ->
+      @err.message.should.equal @message
+      done()