Schema: Move node-selection's href and user-content into choice

[AirQuick]

This pull request derives from #306. So needs to be handled after that.

Obsoletes #171.

---

In the current schema, node-selection makes both href and user-content optional:

xspec/src/schemas/xspec.rnc

Lines 190 to 195 in 5c87ec0

	node-selection =
	## The document URI (location) of the imported document.
	attribute href { xs:anyURI }?,
	## The XPath expression to access the selected node.
	attribute select { xpath }?,
	user-content

xspec/src/schemas/xspec.rnc

Line 215 in 5c87ec0

user-content = mixed { user-element* }

So it allows these elements

<x:context href="uri">content</x:context>

<x:param href="uri" name="foo">content</x:param>

<x:expect href="uri" label="foo">content</x:expect>

which don't make sense.

As for x:context, the scenario is terminated:

xspec/src/compiler/generate-xspec-tests.xsl

Lines 125 to 132 in 5c87ec0

	<xsl:if test="$context/@href and ($context/node() except $context/x:param)">
	<xsl:message terminate="yes">
	<xsl:text>ERROR in scenario "</xsl:text>
	<xsl:value-of select="x:label(.)" />
	<xsl:text>": can't set the context document using both the href</xsl:text>
	<xsl:text> attribute and the content of &lt;context&gt;</xsl:text>
	</xsl:message>
	</xsl:if>

As for x:param and x:expect, content is ignored in favor of @href:

xspec/src/compiler/generate-tests-helper.xsl

Lines 51 to 66 in 5c87ec0

	<variable name="{$var}-doc" as="document-node()">
	<xsl:choose>
	<xsl:when test="@href">
	<xsl:attribute name="select">
	<xsl:text>doc('</xsl:text>
	<xsl:value-of select="resolve-uri(@href, base-uri(.))" />
	<xsl:text>')</xsl:text>
	</xsl:attribute>
	</xsl:when>
	<xsl:otherwise>
	<document>
	<xsl:apply-templates mode="test:create-xslt-generator" />
	</document>
	</xsl:otherwise>
	</xsl:choose>
	</variable>

This pull request updates the schema to reflect it. The elements above are no longer allowed by the updated schema.

This pull request consists of three commits:

• 3c01377 verifies that the implementation does select href over user-content.
• f654c1b updates the schema.
• d2fc959 verifies that the schema does detect violation.

[AirQuick]

Although this pull request contains a lot of commits for historical reasons, all that needs to be reviewed in the end is a set of commits mentioned in the initial comment:

• 3c01377 verifies that the implementation does select href over user-content.
• f654c1b updates the schema.
• d2fc959 verifies that the schema does detect violation.

[galtm]

Commits 3c01377 and f654c1b look good to me. (I had one minor line-specific comment that you can take or leave.) I need a little more time to review d2fc959 so I can become familiar with those files.

[AirQuick]

Thanks @galtm for the review. It's very helpful.

If you're interested, test/xspec.bats is Bats for *nix. Its syntax is written in its doc ("Writing tests" section).

So, in the commit, the test runs Jing to validate test/xspec-node-selection.xspec using src/schemas/xspec.rnc schema. And then the test verifies that Jing outputs exactly 5 violation lines and that every line contains -child-not-allowed. The test result on Travis is here.

test/win-bats/collection.xml is for Windows. Just a mimic of Bats. Its result on AppVeyor is here.

If you're not interested in d2fc959, feel free to review it just shallowly.

[galtm]

If you're interested,

Thanks for the background information, @AirQuick. You saved me some time. The tests look good.

[galtm]

Reviewed the three commits, and they look fine.

[AirQuick]

@cirulls
Merged this PR with the help from @galtm.
This is labeled as enhancement because it improves user experience. But some may call it a bug fix in that the schema didn't reflect the design correctly.

[cirulls]

Thanks. I recorded it in the release notes as enhancement/new feature.