diff --git a/projects/SelfTest/Baselines/console.std.approved.txt b/projects/SelfTest/Baselines/console.std.approved.txt
index a97b7a3a..5c9783cb 100644
--- a/projects/SelfTest/Baselines/console.std.approved.txt
+++ b/projects/SelfTest/Baselines/console.std.approved.txt
@@ -759,7 +759,7 @@ warning:
   error
 
 -------------------------------------------------------------------------------
-A failing expression with a non streamable type is still captured[failing]
+A failing expression with a non streamable type is still captured
 -------------------------------------------------------------------------------
 TrickyTests.cpp:<line number>
 ...............................................................................
@@ -775,7 +775,7 @@ with expansion:
   {?} == {?}
 
 -------------------------------------------------------------------------------
-string literals of different sizes can be compared[failing]
+string literals of different sizes can be compared
 -------------------------------------------------------------------------------
 TrickyTests.cpp:<line number>
 ...............................................................................
@@ -786,6 +786,6 @@ with expansion:
   "first" == "second"
 
 ===============================================================================
-test cases: 148 | 109 passed | 38 failed |  1 failed as expected
-assertions: 739 | 647 passed | 79 failed | 13 failed as expected
+test cases: 149 | 110 passed | 38 failed |  1 failed as expected
+assertions: 751 | 659 passed | 79 failed | 13 failed as expected
 
diff --git a/projects/SelfTest/Baselines/console.sw.approved.txt b/projects/SelfTest/Baselines/console.sw.approved.txt
index 7f6be8ec..682a2ac7 100644
--- a/projects/SelfTest/Baselines/console.sw.approved.txt
+++ b/projects/SelfTest/Baselines/console.sw.approved.txt
@@ -4518,6 +4518,120 @@ with expansion:
           five
           six"
 
+-------------------------------------------------------------------------------
+replaceInPlace
+  replace single char
+-------------------------------------------------------------------------------
+TestMain.cpp:<line number>
+...............................................................................
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( replaceInPlace( letters, "b", "z" ) )
+with expansion:
+  true
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( letters == "azcdefcg" )
+with expansion:
+  "azcdefcg" == "azcdefcg"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  replace two chars
+-------------------------------------------------------------------------------
+TestMain.cpp:<line number>
+...............................................................................
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( replaceInPlace( letters, "c", "z" ) )
+with expansion:
+  true
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( letters == "abzdefzg" )
+with expansion:
+  "abzdefzg" == "abzdefzg"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  replace first char
+-------------------------------------------------------------------------------
+TestMain.cpp:<line number>
+...............................................................................
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( replaceInPlace( letters, "a", "z" ) )
+with expansion:
+  true
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( letters == "zbcdefcg" )
+with expansion:
+  "zbcdefcg" == "zbcdefcg"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  replace last char
+-------------------------------------------------------------------------------
+TestMain.cpp:<line number>
+...............................................................................
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( replaceInPlace( letters, "g", "z" ) )
+with expansion:
+  true
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( letters == "abcdefcz" )
+with expansion:
+  "abcdefcz" == "abcdefcz"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  replace all chars
+-------------------------------------------------------------------------------
+TestMain.cpp:<line number>
+...............................................................................
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( replaceInPlace( letters, letters, "replaced" ) )
+with expansion:
+  true
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( letters == "replaced" )
+with expansion:
+  "replaced" == "replaced"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  replace no chars
+-------------------------------------------------------------------------------
+TestMain.cpp:<line number>
+...............................................................................
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK_FALSE( replaceInPlace( letters, "x", "z" ) )
+with expansion:
+  !false
+
+TestMain.cpp:<line number>:
+PASSED:
+  CHECK( letters == letters )
+with expansion:
+  "abcdefcg" == "abcdefcg"
+
 hello
 hello
 -------------------------------------------------------------------------------
@@ -5604,7 +5718,7 @@ warning:
 No assertions in test case 'Where the LHS is not a simple value[failing]'
 
 -------------------------------------------------------------------------------
-A failing expression with a non streamable type is still captured[failing]
+A failing expression with a non streamable type is still captured
 -------------------------------------------------------------------------------
 TrickyTests.cpp:<line number>
 ...............................................................................
@@ -5620,7 +5734,7 @@ with expansion:
   {?} == {?}
 
 -------------------------------------------------------------------------------
-string literals of different sizes can be compared[failing]
+string literals of different sizes can be compared
 -------------------------------------------------------------------------------
 TrickyTests.cpp:<line number>
 ...............................................................................
@@ -7683,6 +7797,6 @@ with expansion:
   true
 
 ===============================================================================
-test cases: 148 |  93 passed | 54 failed |  1 failed as expected
-assertions: 759 | 647 passed | 99 failed | 13 failed as expected
+test cases: 149 |  94 passed | 54 failed |  1 failed as expected
+assertions: 771 | 659 passed | 99 failed | 13 failed as expected
 
diff --git a/projects/SelfTest/Baselines/junit.sw.approved.txt b/projects/SelfTest/Baselines/junit.sw.approved.txt
index 7529791d..b65529c7 100644
--- a/projects/SelfTest/Baselines/junit.sw.approved.txt
+++ b/projects/SelfTest/Baselines/junit.sw.approved.txt
@@ -1,5 +1,5 @@
 <testsuites>
-  <testsuite name="all tests" errors="12" failures="87" tests="759" hostname="tbd" time="{duration}" timestamp="tbd">
+  <testsuite name="all tests" errors="12" failures="87" tests="771" hostname="tbd" time="{duration}" timestamp="tbd">
     <testcase classname="global" name="toString(enum)" time="{duration}"/>
     <testcase classname="global" name="toString(enum w/operator&lt;&lt;)" time="{duration}"/>
     <testcase classname="global" name="toString(enum class)" time="{duration}"/>
@@ -485,6 +485,12 @@ MiscTests.cpp:<line number>
     <testcase classname="Long strings can be wrapped" name="With newlines/Wrapped once" time="{duration}"/>
     <testcase classname="Long strings can be wrapped" name="With newlines/Wrapped twice" time="{duration}"/>
     <testcase classname="Long strings can be wrapped" name="With tabs" time="{duration}"/>
+    <testcase classname="replaceInPlace" name="replace single char" time="{duration}"/>
+    <testcase classname="replaceInPlace" name="replace two chars" time="{duration}"/>
+    <testcase classname="replaceInPlace" name="replace first char" time="{duration}"/>
+    <testcase classname="replaceInPlace" name="replace last char" time="{duration}"/>
+    <testcase classname="replaceInPlace" name="replace all chars" time="{duration}"/>
+    <testcase classname="replaceInPlace" name="replace no chars" time="{duration}"/>
     <testcase classname="global" name="Strings can be rendered with colour" time="{duration}">
       <system-out>
 hello
@@ -496,7 +502,7 @@ hello
     <testcase classname="global" name="Parsing a std::pair" time="{duration}"/>
     <testcase classname="global" name="Where the is more to the expression after the RHS[failing]" time="{duration}"/>
     <testcase classname="global" name="Where the LHS is not a simple value[failing]" time="{duration}"/>
-    <testcase classname="global" name="A failing expression with a non streamable type is still captured[failing]" time="{duration}">
+    <testcase classname="global" name="A failing expression with a non streamable type is still captured" time="{duration}">
       <failure message="0x<hex digits> == 0x<hex digits>" type="CHECK">
 TrickyTests.cpp:<line number>
       </failure>
@@ -504,7 +510,7 @@ TrickyTests.cpp:<line number>
 TrickyTests.cpp:<line number>
       </failure>
     </testcase>
-    <testcase classname="global" name="string literals of different sizes can be compared[failing]" time="{duration}">
+    <testcase classname="global" name="string literals of different sizes can be compared" time="{duration}">
       <failure message="&quot;first&quot; == &quot;second&quot;" type="REQUIRE">
 TrickyTests.cpp:<line number>
       </failure>
diff --git a/projects/SelfTest/Baselines/xml.sw.approved.txt b/projects/SelfTest/Baselines/xml.sw.approved.txt
index 612ed0bf..54ac8624 100644
--- a/projects/SelfTest/Baselines/xml.sw.approved.txt
+++ b/projects/SelfTest/Baselines/xml.sw.approved.txt
@@ -4714,6 +4714,123 @@ four&quot;
       </Section>
       <OverallResult success="true"/>
     </TestCase>
+    <TestCase name="replaceInPlace">
+      <Section name="replace single char">
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            replaceInPlace( letters, &quot;b&quot;, &quot;z&quot; )
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            letters == &quot;azcdefcg&quot;
+          </Original>
+          <Expanded>
+            &quot;azcdefcg&quot; == &quot;azcdefcg&quot;
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="replace two chars">
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            replaceInPlace( letters, &quot;c&quot;, &quot;z&quot; )
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            letters == &quot;abzdefzg&quot;
+          </Original>
+          <Expanded>
+            &quot;abzdefzg&quot; == &quot;abzdefzg&quot;
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="replace first char">
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            replaceInPlace( letters, &quot;a&quot;, &quot;z&quot; )
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            letters == &quot;zbcdefcg&quot;
+          </Original>
+          <Expanded>
+            &quot;zbcdefcg&quot; == &quot;zbcdefcg&quot;
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="replace last char">
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            replaceInPlace( letters, &quot;g&quot;, &quot;z&quot; )
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            letters == &quot;abcdefcz&quot;
+          </Original>
+          <Expanded>
+            &quot;abcdefcz&quot; == &quot;abcdefcz&quot;
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="replace all chars">
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            replaceInPlace( letters, letters, &quot;replaced&quot; )
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            letters == &quot;replaced&quot;
+          </Original>
+          <Expanded>
+            &quot;replaced&quot; == &quot;replaced&quot;
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="replace no chars">
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            !replaceInPlace( letters, &quot;x&quot;, &quot;z&quot; )
+          </Original>
+          <Expanded>
+            !false
+          </Expanded>
+        </Expression>
+        <Expression success="true" filename="projects/SelfTest/TestMain.cpp" >
+          <Original>
+            letters == letters
+          </Original>
+          <Expanded>
+            &quot;abcdefcg&quot; == &quot;abcdefcg&quot;
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <OverallResult success="true"/>
+    </TestCase>
     <TestCase name="Strings can be rendered with colour">
       <OverallResult success="true"/>
     </TestCase>
@@ -5774,7 +5891,7 @@ there&quot;
       </Warning>
       <OverallResult success="true"/>
     </TestCase>
-    <TestCase name="A failing expression with a non streamable type is still captured[failing]">
+    <TestCase name="A failing expression with a non streamable type is still captured">
       <Expression success="false" filename="projects/SelfTest/TrickyTests.cpp" >
         <Original>
           &amp;o1 == &amp;o2
@@ -5793,7 +5910,7 @@ there&quot;
       </Expression>
       <OverallResult success="false"/>
     </TestCase>
-    <TestCase name="string literals of different sizes can be compared[failing]">
+    <TestCase name="string literals of different sizes can be compared">
       <Expression success="false" filename="projects/SelfTest/TrickyTests.cpp" >
         <Original>
           std::string( &quot;first&quot; ) == &quot;second&quot;
@@ -7950,7 +8067,7 @@ there&quot;
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <OverallResults successes="647" failures="99" expectedFailures="13"/>
+    <OverallResults successes="659" failures="99" expectedFailures="13"/>
   </Group>
-  <OverallResults successes="647" failures="99" expectedFailures="13"/>
+  <OverallResults successes="659" failures="99" expectedFailures="13"/>
 </Catch>