Add comparison of element attributes (#3)

Author: stringbean

.travis.yml

@@ -1,25 +1,27 @@
 language: scala
 sudo: false
 
-scala:
-  - 2.11.11
-  - 2.12.7
-  - 2.13.0-M5
 jdk:
-  - oraclejdk8
+  - openjdk8
+  - openjdk11
 
-# cache config taken from http://www.scala-sbt.org/0.13/docs/Travis-CI-with-sbt.html
 cache:
   directories:
-    - $HOME/.ivy2/cache
-    - $HOME/.sbt/boot/
+    - $HOME/.cache
+    - $HOME/.sbt
 
 before_cache:
-  - find $HOME/.ivy2 -name "ivydata-*.properties" -delete
+  - find $HOME/.ivy2 -name "*.lock" -delete
   - find $HOME/.sbt -name "*.lock" -delete
 
 # build with scoverage report and upload to codecov
-script:
-  - sbt ++$TRAVIS_SCALA_VERSION coverage test coverageReport coverageAggregate
-after_success:
-  - bash <(curl -s https://codecov.io/bash)
+
+jobs:
+  include:
+    # run tests against all Scala versions & JDKs
+    - stage: Test
+      script: sbt +test
+    # coverage only runs on 2.12 openjdk8
+    - stage: Coverage
+      script: sbt ++2.12.10 coverage test coverageReport coverageAggregate && bash <(curl -s https://codecov.io/bash)
+

build.sbt

@@ -60,9 +60,10 @@ lazy val root = Project("scala-xml-compare", file("."))
     // site/paradox
     siteSubdirName in ScalaUnidoc := "api",
     addMappingsToSiteDir(mappings in (ScalaUnidoc, packageDoc), siteSubdirName in ScalaUnidoc),
-    paradoxProperties in Paradox ++= Map(
-      "scaladoc.software.purpledragon.xml.base_url" -> ".../api"
+    paradoxProperties in Compile ++= Map(
+      "scaladoc.base_url" -> ".../api"
     ),
+    paradoxNavigationDepth := 3,
     scalacOptions in Compile in doc ++= Seq(
       "-doc-root-content",
       baseDirectory.value + "/root-scaladoc.txt"

project/plugins.sbt

@@ -1,6 +1,6 @@
 // code style
 addSbtPlugin("org.scalastyle" %% "scalastyle-sbt-plugin" % "1.0.0")
-addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.6.0-M5")
+addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.6.0")
 addSbtPlugin("com.lucidchart" % "sbt-scalafmt" % "1.15")
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.0.0")
 

src/main/paradox/comparing-xml.md

@@ -1,8 +1,127 @@
 # Comparing XML
 
+A simple XML comparison can be performed using
+@scaladoc[`XmlCompare.compare`](software.purpledragon.xml.compare.XmlCompare$): 
+
+```scala
+// using XML literals:
+val result = XmlCompare.compare(<test/>, <test/>) // == XmlEqual
+
+// or from a file:
+val success = XmlCompare.compare(<result><success/></result>, XML.loadFile("result.xml"))
+```
+
+The way that XML is compared can be customised by supplying a `Set` of
+@scaladoc[`DiffOption`s](software.purpledragon.xml.compare.options.DiffOption$):
+
+```scala
+// this would result an XmlEqual
+XmlCompare.compare(
+  <test name="John" age="45"/>,
+  <test age="45" name="John"/>)
+
+// this would result an XmlDiffers
+XmlCompare.compare(
+  <test name="John" age="45"/>,
+  <test age="45" name="John"/>,
+  Set(DiffOption.StrictAttributeOrdering))
+```
+
+@ref:[Comparison Options](#comparison-options) contains details of the supported options.
+
+## Comparison Results
+
+`XmlCompare.compare` returns an @scaladoc[`XmlDiff`](software.purpledragon.xml.compare.XmlDiff) that will either be
+@scaladoc[`XmlEqual`](software.purpledragon.xml.compare.XmlEqual) or a detailed 
+@scaladoc[`XmlDiffers`](software.purpledragon.xml.compare.XmlDiffers). If a simple
+pass/fail check is required then the `isEqual` method can be called on the result.
+
+### XmlEqual
+
+An `XmlEqual` result signifies that no differences in the XML were found.
+
+### XmlDiffers
+
+An `XmlDiffers` result will contain the _first_ difference found in the XML. The `reason` property will have a
+human-readable reason for the difference, `left` & `right` will have the differences and `failurePath` will have the
+path segments to the difference. 
+
+For example:
+ 
+```scala
+XmlDiffers(
+  "different attribute ordering",
+  Seq("first", "second"),
+  Seq("second", "first"),
+  Seq("test")
+)
+```
 
 ## Comparison Options
 
 By default the following options are used:
 
 * `IgnoreNamespacePrefix`
+
+### IgnoreNamespacePrefix
+
+If enabled the prefixes associated with namespaces will be ignored. Differing namespaces will still cause a comparison
+error.
+
+#### Example
+
+This:
+```xml
+<t:example xmlns:t="http://example.com">5</t:example>
+```
+
+would be considered equal to:
+```xml
+<f:example xmlns:f="http://example.com">5</f:example>
+```
+
+### IgnoreNamespace
+
+If enabled then namespaces will be ignored completely.
+
+#### Example
+
+This:
+```xml
+<t:example xmlns:t="http://example.com">5</t:example>
+```
+
+would be considered equal to:
+```xml
+<f:example xmlns:f="http://example.org">5</f:example>
+```
+
+### StrictAttributeOrdering
+
+This adds an additional comparison on the ordering of element attributes. The presence of attributes will be checked
+_before_ the ordering.
+
+#### Example
+
+This:
+
+```xml
+<example first="a" second="b" />
+```
+
+would not be equal to:
+
+```xml
+<example second="b" first="a" />
+```
+
+and would result in the following failure:
+
+```scala
+XmlDiffers(
+  "different attribute ordering",
+  Seq("first", "second"),
+  Seq("second", "first"),
+  Seq("test")
+)
+```

xml-compare/src/main/scala/software/purpledragon/xml/compare/XmlCompare.scala

@@ -51,6 +51,7 @@ object XmlCompare {
   private def compareNodes(left: Node, right: Node, options: DiffOptions, path: Seq[String]): XmlDiff = {
     val checks: Seq[Check] = Seq(
       compareNamespace,
+      compareAttributes,
       compareText,
       compareChildren
     )
@@ -78,6 +79,29 @@ object XmlCompare {
     }
   }
 
+  private def compareAttributes(left: Node, right: Node, options: DiffOptions, path: Seq[String]): XmlDiff = {
+    def extractAttributes(node: Node): (Seq[String], Map[String, String]) = {
+      node.attributes.foldLeft(Seq.empty[String], Map.empty[String, String]) {
+        case ((keys, attribs), attrib) =>
+          (keys :+ attrib.key, attribs + (attrib.key -> attrib.value.text))
+      }
+    }
+
+    val (leftKeys, leftMap) = extractAttributes(left)
+    val (rightKeys, rightMap) = extractAttributes(right)
+
+    if (leftKeys.sorted != rightKeys.sorted) {
+      XmlDiffers("different attribute names", leftKeys.sorted, rightKeys.sorted, extendPath(path, left))
+    } else if (options.contains(StrictAttributeOrdering) && leftKeys != rightKeys) {
+      XmlDiffers("different attribute ordering", leftKeys, rightKeys, extendPath(path, left))
+    } else {
+      leftKeys.sorted collectFirst {
+        case name if leftMap(name) != rightMap(name) =>
+          XmlDiffers(s"different value for attribute '$name'", leftMap(name), rightMap(name), extendPath(path, left))
+      } getOrElse XmlEqual
+    }
+  }
+
   private def compareText(left: Node, right: Node, options: DiffOptions, path: Seq[String]): XmlDiff = {
     def extractText(node: Node): String = node.child.collect({ case a: Atom[_] => a }).map(_.text.trim).mkString
     val leftText = extractText(left)

xml-compare/src/main/scala/software/purpledragon/xml/compare/options/DiffOption.scala

@@ -49,4 +49,18 @@ object DiffOption extends Enumeration {
    * }}}
    */
   val IgnoreNamespace: DiffOption.Value = Value
+
+  /**
+   * Require element attributes have the same ordering.
+   *
+   * Enabling this make this:
+   * {{{
+   *   <example first="a" second="b" />
+   * }}}
+   * not equal to:
+   * {{{
+   *   <example second="b" first="a" />
+   * }}}
+   */
+  val StrictAttributeOrdering: DiffOption.Value = Value
 }

xml-compare/src/test/scala/software/purpledragon/xml/compare/XmlCompareSpec.scala

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2017 Michael Stringer
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package software.purpledragon.xml.compare
 
 import org.scalatest.{FlatSpec, Matchers}
@@ -80,6 +96,41 @@ class XmlCompareSpec extends FlatSpec with Matchers {
     )
   }
 
+  it should "match with same attributes" in {
+    XmlCompare.compare(<test first="a" second="b"/>, <test first="a" second="b" />) shouldBe XmlEqual
+  }
+
+  it should "match with same attributes in different order" in {
+    XmlCompare.compare(<test first="a" second="b"/>, <test second="b" first="a" />) shouldBe XmlEqual
+  }
+
+  it should "not-match with different attribute names" in {
+    XmlCompare.compare(<test value="a" />, <test cost="a" />) shouldBe XmlDiffers(
+      "different attribute names",
+      Seq("value"),
+      Seq("cost"),
+      Seq("test")
+    )
+  }
+
+  it should "not-match with different attribute count" in {
+    XmlCompare.compare(<test first="a" second="b" />, <test first="a" />) shouldBe XmlDiffers(
+      "different attribute names",
+      Seq("first", "second"),
+      Seq("first"),
+      Seq("test")
+    )
+  }
+
+  it should "not-match with different attribute value" in {
+    XmlCompare.compare(<test value="a" />, <test value="b" />) shouldBe XmlDiffers(
+      "different value for attribute 'value'",
+      "a",
+      "b",
+      Seq("test")
+    )
+  }
+
   it should "not-match with multiple errors" in {
     XmlCompare.compare(
       <test><child-1>text-1</child-1><child-2>text-2</child-2></test>,
@@ -115,4 +166,17 @@ class XmlCompareSpec extends FlatSpec with Matchers {
       <t:test xmlns:e="http://example.org"/>,
       Set(IgnoreNamespace)) shouldBe XmlEqual
   }
+
+  "compare with StrictAttributeOrder" should "match with same attributes" in {
+    XmlCompare.compare(<test first="a" second="b" />, <test first="a" second="b" />, Set(StrictAttributeOrdering)) shouldBe XmlEqual
+  }
+
+  it should "not-match with attributes in different order" in {
+    XmlCompare.compare(<test first="a" second="b" />, <test second="b" first="a" />, Set(StrictAttributeOrdering)) shouldBe XmlDiffers(
+      "different attribute ordering",
+      Seq("first", "second"),
+      Seq("second", "first"),
+      Seq("test")
+    )
+  }
 }