Remove version(dxmlTests)

Previously, there was a problem where if someone imported a dxml module
from their unit tests, they would get linker errors about symbols that
dxml's unit tests imported not being found, and I couldn't figure out
why. The solution was to declare the version identifier dxmlTests and
using version(dxmlTests) on all of the unittest blocks and anything that
had been version(unittest), which meant that dub test then didn't work
without providing a custom build type which defined dxmlTests. It
worked, but it was ugly.

Now, I've finally figured out what the problem was. In order to
instantiate the templated types so that their tests would be compiled
and run, for each templated type, a module-level variable was being
declared (originally as version(unittest) and then version(dxmlTests))
which instantiated the type with the correct type to compile in the
tests. With version(unittest), that variable was declared when another
project imported the module when building their unit tests, which meant
that the template was instantiated and the tests were compiled - and
then failed to compile because of symbols that weren't available.

So, by moving those variables to unittest blocks, they only get compiled
(and thus, the templates only gets instantiated with their tests) when
compiling dxml's unit tests and not when another project using dxml
compiles its tests. So, the version identifier dxmlTests is no longer
necessary, and dub test works properly again.

cov.sh

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-dub test --build=doCov
+dub test --build=unittest-cov

dub.json

@@ -2,25 +2,14 @@
     "name": "dxml",
     "authors": [ "Jonathan M Davis" ],
     "description": "An XML parser and writer written in D.",
-    "copyright": "Copyright © 2017 - 2018, Jonathan M Davis",
+    "copyright": "Copyright © 2017 - 2019, Jonathan M Davis",
     "license": "BSL-1.0",
     "targetType": "library",
     "buildTypes":
     {
-        "doTests":
+        "unittest-release":
         {
-            "buildOptions": ["unittests", "debugMode", "debugInfo"],
-            "versions": ["dxmlTests"]
-        },
-        "doReleaseTests":
-        {
-            "buildOptions": ["unittests", "debugMode", "debugInfo", "releaseMode"],
-            "versions": ["dxmlTests"]
-        },
-        "doCov":
-        {
-            "buildOptions": ["unittests", "debugMode", "debugInfo", "coverage"],
-            "versions": ["dxmlTests"]
+            "buildOptions": ["unittests", "debugMode", "debugInfo", "releaseMode"]
         }
     }
 }

source/dxml/dom.d

@@ -16,7 +16,7 @@
     $(REF_ALTTEXT simpleXML, simpleXML, dxml, parser) is highly likely to
     be used when calling $(LREF parseDOM).
 
-    Copyright: Copyright 2018
+    Copyright: Copyright 2018 - 2019
     License:   $(HTTP www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
     Authors:   $(HTTPS jmdavisprog.com, Jonathan M Davis)
     Source:    $(LINK_TO_SRC dxml/_dom.d)
@@ -26,7 +26,7 @@
 module dxml.dom;
 
 ///
-version(dxmlTests) unittest
+unittest
 {
     import std.range.primitives : empty;
 
@@ -825,7 +825,7 @@ DOMEntity!(ER.Input) parseDOM(ER)(ref ER range)
     parseDOM with the default $(REF_ALTTEXT Config, Config, dxml, parser) and a
     range of characters.
   +/
-version(dxmlTests) @safe unittest
+@safe unittest
 {
     import std.range.primitives;
 
@@ -876,7 +876,7 @@ version(dxmlTests) @safe unittest
     parseDOM with $(REF_ALTTEXT simpleXML, simpleXML, dxml, parser) and a range
     of characters.
   +/
-version(dxmlTests) unittest
+unittest
 {
     import std.range.primitives : empty;
 
@@ -925,7 +925,7 @@ version(dxmlTests) unittest
     parseDOM with $(REF_ALTTEXT simpleXML, simpleXML, dxml, parser) and an
     $(REF_ALTTEXT EntityRange, EntityRange, dxml, parser).
   +/
-version(dxmlTests) unittest
+unittest
 {
     import std.range.primitives : empty;
     import dxml.parser : parseXML;
@@ -978,7 +978,7 @@ version(dxmlTests) unittest
     parseDOM with an $(REF_ALTTEXT EntityRange, EntityRange, dxml, parser)
     which is not at the start of the document.
   +/
-version(dxmlTests) unittest
+unittest
 {
     import std.range.primitives : empty;
     import dxml.parser : parseXML, skipToPath;
@@ -1014,7 +1014,7 @@ version(dxmlTests) unittest
 }
 
 /// parseDOM at compile-time
-version(dxmlTests) unittest
+unittest
 {
     enum xml = "<!-- comment -->\n" ~
                "<root>\n" ~
@@ -1042,8 +1042,10 @@ private struct DOMCompileTests
     @property typeof(this) save() @safe pure nothrow @nogc { assert(0); }
 }
 
-version(dxmlTests)
+unittest
+{
     DOMEntity!DOMCompileTests _domTests;
+}
 
 
 private:
@@ -1115,7 +1117,7 @@ void _parseDOM(ER, DE)(ref ER range, ref DE parent, ER.SliceOfR[] path = null)
     parent._children = children.data;
 }
 
-version(dxmlTests) unittest
+unittest
 {
     import std.algorithm.comparison : equal;
     import dxml.internal : testRangeFuncs;

source/dxml/internal.d

@@ -1,7 +1,7 @@
 // Written in the D programming language
 
 /+
-    Copyright: Copyright 2017 - 2018
+    Copyright: Copyright 2017 - 2019
     License:   $(WEB www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
     Authors:   Jonathan M Davis
   +/
@@ -36,7 +36,7 @@ bool equalCU(R)(R range, string text)
     return range.empty;
 }
 
-version(dxmlTests) unittest
+unittest
 {
     import std.algorithm : filter;
     import std.meta : AliasSeq;
@@ -87,7 +87,7 @@ pragma(inline, true) auto stripBCU(Orig, R)(R range)
         return range;
 }
 
-version(dxmlTests) unittest
+unittest
 {
     import std.algorithm : equal, filter;
     import std.range : takeExactly;
@@ -132,7 +132,7 @@ bool isXMLChar(dchar c) pure nothrow @safe @nogc
                       : c > 127 && (c <= 0xD7FF || (c >= 0xE000 && c <= 0xFFFD) || (c >= 0x10000 && c <= 0x10FFFF));
 }
 
-version(dxmlTests) pure nothrow @safe @nogc unittest
+pure nothrow @safe @nogc unittest
 {
     import std.range : only;
     import std.typecons : tuple;
@@ -205,7 +205,7 @@ bool isNameStartChar(dchar c) @safe pure nothrow @nogc
     return false;
 }
 
-version(dxmlTests) pure nothrow @safe @nogc unittest
+pure nothrow @safe @nogc unittest
 {
     import std.range : only;
     import std.typecons : tuple;
@@ -253,7 +253,7 @@ bool isNameChar(dchar c) @safe pure nothrow @nogc
            c >= 0x0300 && c <= 0x036F || c >= 0x203F && c <= 0x2040;
 }
 
-version(dxmlTests) pure nothrow @safe @nogc unittest
+pure nothrow @safe @nogc unittest
 {
     import std.ascii : isAlphaNum;
     import std.range : only;
@@ -299,7 +299,7 @@ version(dxmlTests) pure nothrow @safe @nogc unittest
 // Unit test helpers
 //------------------------------------------------------------------------------
 
-version(dxmlTests):
+version(unittest):
 
 struct FwdCharRange(C)
 {