Better support for infs and NaNs in JSON writer

As the types and values sent into the writer are determined by Catch2,
I do not expect to actually need this support, but it is better to have
it and not be surprised in the future.

18 files changed, 411 insertions, 18 deletions

diff --git a/tests/SelfTest/Baselines/automake.sw.approved.txt b/tests/SelfTest/Baselines/automake.sw.approved.txt
index b0028998..a25bc52a 100644
--- a/tests/SelfTest/Baselines/automake.sw.approved.txt
+++ b/tests/SelfTest/Baselines/automake.sw.approved.txt
@@ -190,6 +190,8 @@ Nor would this
 :test-result: PASS Inequality checks that should succeed
 :test-result: PASS JsonWriter
 :test-result: PASS JsonWriter escapes characters in strings properly
+:test-result: PASS JsonWriter serializes non-finite FP using Python spelling - double
+:test-result: PASS JsonWriter serializes non-finite FP using Python spelling - float
 :test-result: PASS JsonWriter serializes numbers independently of the global locale
 :test-result: PASS Lambdas in assertions
 :test-result: PASS Less-than inequalities with different epsilons
diff --git a/tests/SelfTest/Baselines/automake.sw.multi.approved.txt b/tests/SelfTest/Baselines/automake.sw.multi.approved.txt
index 9602395a..3f846b7b 100644
--- a/tests/SelfTest/Baselines/automake.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/automake.sw.multi.approved.txt
@@ -188,6 +188,8 @@
 :test-result: PASS Inequality checks that should succeed
 :test-result: PASS JsonWriter
 :test-result: PASS JsonWriter escapes characters in strings properly
+:test-result: PASS JsonWriter serializes non-finite FP using Python spelling - double
+:test-result: PASS JsonWriter serializes non-finite FP using Python spelling - float
 :test-result: PASS JsonWriter serializes numbers independently of the global locale
 :test-result: PASS Lambdas in assertions
 :test-result: PASS Less-than inequalities with different epsilons
diff --git a/tests/SelfTest/Baselines/compact.sw.approved.txt b/tests/SelfTest/Baselines/compact.sw.approved.txt
index d669bce4..7989d276 100644
--- a/tests/SelfTest/Baselines/compact.sw.approved.txt
+++ b/tests/SelfTest/Baselines/compact.sw.approved.txt
@@ -1248,6 +1248,12 @@ Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\n\"" for: ""\n"" ==
 Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\r\"" for: ""\r"" == ""\r""
 Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\t\"" for: ""\t"" == ""\t""
 Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\\\/\\t\\r\\n\"" for: ""\\/\t\r\n"" == ""\\/\t\r\n""
+Json.tests.cpp:<line number>: passed: sstream.str() == "NaN" for: "NaN" == "NaN"
+Json.tests.cpp:<line number>: passed: sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+Json.tests.cpp:<line number>: passed: sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
+Json.tests.cpp:<line number>: passed: sstream.str() == "NaN" for: "NaN" == "NaN"
+Json.tests.cpp:<line number>: passed: sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+Json.tests.cpp:<line number>: passed: sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
 Json.tests.cpp:<line number>: passed: sstream.str(), ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"int\": 1234567," ) && ContainsSubstring( "\"bool-1\": true," ) && ContainsSubstring( "\"bool-2\": false," ) && ContainsSubstring( "\"array\": [\n    2.5,\n    1234567\n  ]\n}" ) for: "{
   "double": 1.5,
   "int": 1234567,
@@ -3014,7 +3020,7 @@ InternalBenchmark.tests.cpp:<line number>: passed: med == 18. for: 18.0 == 18.0
 InternalBenchmark.tests.cpp:<line number>: passed: q3 == 23. for: 23.0 == 23.0
 Misc.tests.cpp:<line number>: passed:
 Misc.tests.cpp:<line number>: passed:
-test cases:  452 |  332 passed |  96 failed | 6 skipped | 18 failed as expected
-assertions: 2417 | 2216 passed | 158 failed | 43 failed as expected
+test cases:  454 |  334 passed |  96 failed | 6 skipped | 18 failed as expected
+assertions: 2423 | 2222 passed | 158 failed | 43 failed as expected
 
 
diff --git a/tests/SelfTest/Baselines/compact.sw.multi.approved.txt b/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
index 712b1259..ffe7a2f6 100644
--- a/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
@@ -1246,6 +1246,12 @@ Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\n\"" for: ""\n"" ==
 Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\r\"" for: ""\r"" == ""\r""
 Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\t\"" for: ""\t"" == ""\t""
 Json.tests.cpp:<line number>: passed: sstream.str() == "\"\\\\/\\t\\r\\n\"" for: ""\\/\t\r\n"" == ""\\/\t\r\n""
+Json.tests.cpp:<line number>: passed: sstream.str() == "NaN" for: "NaN" == "NaN"
+Json.tests.cpp:<line number>: passed: sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+Json.tests.cpp:<line number>: passed: sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
+Json.tests.cpp:<line number>: passed: sstream.str() == "NaN" for: "NaN" == "NaN"
+Json.tests.cpp:<line number>: passed: sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+Json.tests.cpp:<line number>: passed: sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
 Json.tests.cpp:<line number>: passed: sstream.str(), ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"int\": 1234567," ) && ContainsSubstring( "\"bool-1\": true," ) && ContainsSubstring( "\"bool-2\": false," ) && ContainsSubstring( "\"array\": [\n    2.5,\n    1234567\n  ]\n}" ) for: "{
   "double": 1.5,
   "int": 1234567,
@@ -3003,7 +3009,7 @@ InternalBenchmark.tests.cpp:<line number>: passed: med == 18. for: 18.0 == 18.0
 InternalBenchmark.tests.cpp:<line number>: passed: q3 == 23. for: 23.0 == 23.0
 Misc.tests.cpp:<line number>: passed:
 Misc.tests.cpp:<line number>: passed:
-test cases:  452 |  332 passed |  96 failed | 6 skipped | 18 failed as expected
-assertions: 2417 | 2216 passed | 158 failed | 43 failed as expected
+test cases:  454 |  334 passed |  96 failed | 6 skipped | 18 failed as expected
+assertions: 2423 | 2222 passed | 158 failed | 43 failed as expected
 
 
diff --git a/tests/SelfTest/Baselines/console.std.approved.txt b/tests/SelfTest/Baselines/console.std.approved.txt
index a833734a..344c5b03 100644
--- a/tests/SelfTest/Baselines/console.std.approved.txt
+++ b/tests/SelfTest/Baselines/console.std.approved.txt
@@ -1743,6 +1743,6 @@ due to unexpected exception with message:
   Why would you throw a std::string?
 
 ===============================================================================
-test cases:  452 |  350 passed |  76 failed | 7 skipped | 19 failed as expected
-assertions: 2395 | 2216 passed | 136 failed | 43 failed as expected
+test cases:  454 |  352 passed |  76 failed | 7 skipped | 19 failed as expected
+assertions: 2401 | 2222 passed | 136 failed | 43 failed as expected
 
diff --git a/tests/SelfTest/Baselines/console.sw.approved.txt b/tests/SelfTest/Baselines/console.sw.approved.txt
index 2de0a3a5..0729823f 100644
--- a/tests/SelfTest/Baselines/console.sw.approved.txt
+++ b/tests/SelfTest/Baselines/console.sw.approved.txt
@@ -8220,6 +8220,78 @@ with expansion:
   ""\\/\t\r\n"" == ""\\/\t\r\n""
 
 -------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - double
+  NaN
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "NaN" )
+with expansion:
+  "NaN" == "NaN"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - double
+  Pos nf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "Infinity" )
+with expansion:
+  "Infinity" == "Infinity"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - double
+  Neg inf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "-Infinity" )
+with expansion:
+  "-Infinity" == "-Infinity"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - float
+  NaN
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "NaN" )
+with expansion:
+  "NaN" == "NaN"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - float
+  Pos nf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "Infinity" )
+with expansion:
+  "Infinity" == "Infinity"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - float
+  Neg inf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "-Infinity" )
+with expansion:
+  "-Infinity" == "-Infinity"
+
+-------------------------------------------------------------------------------
 JsonWriter serializes numbers independently of the global locale
 -------------------------------------------------------------------------------
 Json.tests.cpp:<line number>
@@ -20159,6 +20231,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  452 |  332 passed |  96 failed | 6 skipped | 18 failed as expected
-assertions: 2417 | 2216 passed | 158 failed | 43 failed as expected
+test cases:  454 |  334 passed |  96 failed | 6 skipped | 18 failed as expected
+assertions: 2423 | 2222 passed | 158 failed | 43 failed as expected
 
diff --git a/tests/SelfTest/Baselines/console.sw.multi.approved.txt b/tests/SelfTest/Baselines/console.sw.multi.approved.txt
index 9b6f023c..3db4bfc8 100644
--- a/tests/SelfTest/Baselines/console.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/console.sw.multi.approved.txt
@@ -8218,6 +8218,78 @@ with expansion:
   ""\\/\t\r\n"" == ""\\/\t\r\n""
 
 -------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - double
+  NaN
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "NaN" )
+with expansion:
+  "NaN" == "NaN"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - double
+  Pos nf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "Infinity" )
+with expansion:
+  "Infinity" == "Infinity"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - double
+  Neg inf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "-Infinity" )
+with expansion:
+  "-Infinity" == "-Infinity"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - float
+  NaN
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "NaN" )
+with expansion:
+  "NaN" == "NaN"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - float
+  Pos nf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "Infinity" )
+with expansion:
+  "Infinity" == "Infinity"
+
+-------------------------------------------------------------------------------
+JsonWriter serializes non-finite FP using Python spelling - float
+  Neg inf
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( sstream.str() == "-Infinity" )
+with expansion:
+  "-Infinity" == "-Infinity"
+
+-------------------------------------------------------------------------------
 JsonWriter serializes numbers independently of the global locale
 -------------------------------------------------------------------------------
 Json.tests.cpp:<line number>
@@ -20148,6 +20220,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  452 |  332 passed |  96 failed | 6 skipped | 18 failed as expected
-assertions: 2417 | 2216 passed | 158 failed | 43 failed as expected
+test cases:  454 |  334 passed |  96 failed | 6 skipped | 18 failed as expected
+assertions: 2423 | 2222 passed | 158 failed | 43 failed as expected
 
diff --git a/tests/SelfTest/Baselines/junit.sw.approved.txt b/tests/SelfTest/Baselines/junit.sw.approved.txt
index c84565d5..f58412b6 100644
--- a/tests/SelfTest/Baselines/junit.sw.approved.txt
+++ b/tests/SelfTest/Baselines/junit.sw.approved.txt
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuitesloose text artifact
 >
-  <testsuite name="<exe-name>" errors="17" failures="141" skipped="12" tests="2429" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="141" skipped="12" tests="2435" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="&quot;*&quot; ~[!nonportable] ~[!benchmark] ~[approvals]"/>
@@ -774,6 +774,14 @@ at Condition.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="JsonWriter escapes characters in strings properly/carriage return in a string is escaped" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="JsonWriter escapes characters in strings properly/tab in a string is escaped" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="JsonWriter escapes characters in strings properly/combination of characters is escaped" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double/NaN" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double/Pos nf" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double/Neg inf" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float/NaN" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float/Pos nf" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float/Neg inf" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="JsonWriter serializes numbers independently of the global locale" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Lambdas in assertions" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Less-than inequalities with different epsilons" time="{duration}" status="run"/>
diff --git a/tests/SelfTest/Baselines/junit.sw.multi.approved.txt b/tests/SelfTest/Baselines/junit.sw.multi.approved.txt
index f4ff03d6..c80e5855 100644
--- a/tests/SelfTest/Baselines/junit.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/junit.sw.multi.approved.txt
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuites>
-  <testsuite name="<exe-name>" errors="17" failures="141" skipped="12" tests="2429" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="141" skipped="12" tests="2435" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="&quot;*&quot; ~[!nonportable] ~[!benchmark] ~[approvals]"/>
@@ -773,6 +773,14 @@ at Condition.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="JsonWriter escapes characters in strings properly/carriage return in a string is escaped" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="JsonWriter escapes characters in strings properly/tab in a string is escaped" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="JsonWriter escapes characters in strings properly/combination of characters is escaped" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double/NaN" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double/Pos nf" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - double/Neg inf" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float/NaN" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float/Pos nf" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter serializes non-finite FP using Python spelling - float/Neg inf" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="JsonWriter serializes numbers independently of the global locale" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Lambdas in assertions" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Less-than inequalities with different epsilons" time="{duration}" status="run"/>
diff --git a/tests/SelfTest/Baselines/sonarqube.sw.approved.txt b/tests/SelfTest/Baselines/sonarqube.sw.approved.txt
index dceaca40..17c26f36 100644
--- a/tests/SelfTest/Baselines/sonarqube.sw.approved.txt
+++ b/tests/SelfTest/Baselines/sonarqube.sw.approved.txt
@@ -262,6 +262,14 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="JsonWriter escapes characters in strings properly/carriage return in a string is escaped" duration="{duration}"/>
     <testCase name="JsonWriter escapes characters in strings properly/tab in a string is escaped" duration="{duration}"/>
     <testCase name="JsonWriter escapes characters in strings properly/combination of characters is escaped" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double/NaN" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double/Pos nf" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double/Neg inf" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float/NaN" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float/Pos nf" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float/Neg inf" duration="{duration}"/>
     <testCase name="JsonWriter serializes numbers independently of the global locale" duration="{duration}"/>
   </file>
   <file path="tests/<exe-name>/IntrospectiveTests/Parse.tests.cpp">
diff --git a/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt b/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt
index 250b45ae..4c113189 100644
--- a/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt
@@ -261,6 +261,14 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="JsonWriter escapes characters in strings properly/carriage return in a string is escaped" duration="{duration}"/>
     <testCase name="JsonWriter escapes characters in strings properly/tab in a string is escaped" duration="{duration}"/>
     <testCase name="JsonWriter escapes characters in strings properly/combination of characters is escaped" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double/NaN" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double/Pos nf" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - double/Neg inf" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float/NaN" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float/Pos nf" duration="{duration}"/>
+    <testCase name="JsonWriter serializes non-finite FP using Python spelling - float/Neg inf" duration="{duration}"/>
     <testCase name="JsonWriter serializes numbers independently of the global locale" duration="{duration}"/>
   </file>
   <file path="tests/<exe-name>/IntrospectiveTests/Parse.tests.cpp">
diff --git a/tests/SelfTest/Baselines/tap.sw.approved.txt b/tests/SelfTest/Baselines/tap.sw.approved.txt
index 7e9a19d6..4ac7f09f 100644
--- a/tests/SelfTest/Baselines/tap.sw.approved.txt
+++ b/tests/SelfTest/Baselines/tap.sw.approved.txt
@@ -2054,6 +2054,18 @@ ok {test-number} - sstream.str() == "\"\\r\"" for: ""\r"" == ""\r""
 ok {test-number} - sstream.str() == "\"\\t\"" for: ""\t"" == ""\t""
 # JsonWriter escapes characters in strings properly
 ok {test-number} - sstream.str() == "\"\\\\/\\t\\r\\n\"" for: ""\\/\t\r\n"" == ""\\/\t\r\n""
+# JsonWriter serializes non-finite FP using Python spelling - double
+ok {test-number} - sstream.str() == "NaN" for: "NaN" == "NaN"
+# JsonWriter serializes non-finite FP using Python spelling - double
+ok {test-number} - sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+# JsonWriter serializes non-finite FP using Python spelling - double
+ok {test-number} - sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
+# JsonWriter serializes non-finite FP using Python spelling - float
+ok {test-number} - sstream.str() == "NaN" for: "NaN" == "NaN"
+# JsonWriter serializes non-finite FP using Python spelling - float
+ok {test-number} - sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+# JsonWriter serializes non-finite FP using Python spelling - float
+ok {test-number} - sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
 # JsonWriter serializes numbers independently of the global locale
 ok {test-number} - sstream.str(), ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"int\": 1234567," ) && ContainsSubstring( "\"bool-1\": true," ) && ContainsSubstring( "\"bool-2\": false," ) && ContainsSubstring( "\"array\": [\n    2.5,\n    1234567\n  ]\n}" ) for: "{   "double": 1.5,   "int": 1234567,   "bool-1": true,   "bool-2": false,   "array": [     2.5,     1234567   ] }" ( contains: ""double": 1.5," and contains: ""int": 1234567," and contains: ""bool-1": true," and contains: ""bool-2": false," and contains: ""array": [     2.5,     1234567   ] }" )
 # Lambdas in assertions
@@ -4853,5 +4865,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2429
+1..2435
 
diff --git a/tests/SelfTest/Baselines/tap.sw.multi.approved.txt b/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
index edcb7813..3f1d56aa 100644
--- a/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
@@ -2052,6 +2052,18 @@ ok {test-number} - sstream.str() == "\"\\r\"" for: ""\r"" == ""\r""
 ok {test-number} - sstream.str() == "\"\\t\"" for: ""\t"" == ""\t""
 # JsonWriter escapes characters in strings properly
 ok {test-number} - sstream.str() == "\"\\\\/\\t\\r\\n\"" for: ""\\/\t\r\n"" == ""\\/\t\r\n""
+# JsonWriter serializes non-finite FP using Python spelling - double
+ok {test-number} - sstream.str() == "NaN" for: "NaN" == "NaN"
+# JsonWriter serializes non-finite FP using Python spelling - double
+ok {test-number} - sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+# JsonWriter serializes non-finite FP using Python spelling - double
+ok {test-number} - sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
+# JsonWriter serializes non-finite FP using Python spelling - float
+ok {test-number} - sstream.str() == "NaN" for: "NaN" == "NaN"
+# JsonWriter serializes non-finite FP using Python spelling - float
+ok {test-number} - sstream.str() == "Infinity" for: "Infinity" == "Infinity"
+# JsonWriter serializes non-finite FP using Python spelling - float
+ok {test-number} - sstream.str() == "-Infinity" for: "-Infinity" == "-Infinity"
 # JsonWriter serializes numbers independently of the global locale
 ok {test-number} - sstream.str(), ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"int\": 1234567," ) && ContainsSubstring( "\"bool-1\": true," ) && ContainsSubstring( "\"bool-2\": false," ) && ContainsSubstring( "\"array\": [\n    2.5,\n    1234567\n  ]\n}" ) for: "{   "double": 1.5,   "int": 1234567,   "bool-1": true,   "bool-2": false,   "array": [     2.5,     1234567   ] }" ( contains: ""double": 1.5," and contains: ""int": 1234567," and contains: ""bool-1": true," and contains: ""bool-2": false," and contains: ""array": [     2.5,     1234567   ] }" )
 # Lambdas in assertions
@@ -4842,5 +4854,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2429
+1..2435
 
diff --git a/tests/SelfTest/Baselines/teamcity.sw.approved.txt b/tests/SelfTest/Baselines/teamcity.sw.approved.txt
index fc65c1c6..16fe73f9 100644
--- a/tests/SelfTest/Baselines/teamcity.sw.approved.txt
+++ b/tests/SelfTest/Baselines/teamcity.sw.approved.txt
@@ -470,6 +470,10 @@
 ##teamcity[testFinished name='JsonWriter' duration="{duration}"]
 ##teamcity[testStarted name='JsonWriter escapes characters in strings properly']
 ##teamcity[testFinished name='JsonWriter escapes characters in strings properly' duration="{duration}"]
+##teamcity[testStarted name='JsonWriter serializes non-finite FP using Python spelling - double']
+##teamcity[testFinished name='JsonWriter serializes non-finite FP using Python spelling - double' duration="{duration}"]
+##teamcity[testStarted name='JsonWriter serializes non-finite FP using Python spelling - float']
+##teamcity[testFinished name='JsonWriter serializes non-finite FP using Python spelling - float' duration="{duration}"]
 ##teamcity[testStarted name='JsonWriter serializes numbers independently of the global locale']
 ##teamcity[testFinished name='JsonWriter serializes numbers independently of the global locale' duration="{duration}"]
 ##teamcity[testStarted name='Lambdas in assertions']
diff --git a/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt b/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt
index f0a28ed7..acc777f2 100644
--- a/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt
@@ -470,6 +470,10 @@
 ##teamcity[testFinished name='JsonWriter' duration="{duration}"]
 ##teamcity[testStarted name='JsonWriter escapes characters in strings properly']
 ##teamcity[testFinished name='JsonWriter escapes characters in strings properly' duration="{duration}"]
+##teamcity[testStarted name='JsonWriter serializes non-finite FP using Python spelling - double']
+##teamcity[testFinished name='JsonWriter serializes non-finite FP using Python spelling - double' duration="{duration}"]
+##teamcity[testStarted name='JsonWriter serializes non-finite FP using Python spelling - float']
+##teamcity[testFinished name='JsonWriter serializes non-finite FP using Python spelling - float' duration="{duration}"]
 ##teamcity[testStarted name='JsonWriter serializes numbers independently of the global locale']
 ##teamcity[testFinished name='JsonWriter serializes numbers independently of the global locale' duration="{duration}"]
 ##teamcity[testStarted name='Lambdas in assertions']
diff --git a/tests/SelfTest/Baselines/xml.sw.approved.txt b/tests/SelfTest/Baselines/xml.sw.approved.txt
index 31801eef..a7f8d3ae 100644
--- a/tests/SelfTest/Baselines/xml.sw.approved.txt
+++ b/tests/SelfTest/Baselines/xml.sw.approved.txt
@@ -9894,6 +9894,78 @@ Approx( 3.14150000000000018 )
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
+  <TestCase name="JsonWriter serializes non-finite FP using Python spelling - double" tags="[floating-point][JsonWriter]" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp"