Add test for filtering out multiple initial values in filter gen

tests/SelfTest/Baselines/compact.sw.approved.txt

@@ -695,7 +695,12 @@ GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
 GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
-GeneratorsImpl.tests.cpp:<line number>: passed: filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: filter([](int) { return false; }, value(1)), Catch::GeneratorException
+GeneratorsImpl.tests.cpp:<line number>: passed: filter([](int) { return false; }, values({ 1, 2, 3 })), Catch::GeneratorException
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 2 for: 2 == 2

tests/SelfTest/Baselines/console.std.approved.txt

@@ -1427,5 +1427,5 @@ due to unexpected exception with message:
 
 ===============================================================================
 test cases:  376 |  299 passed |  70 failed |  7 failed as expected
-assertions: 2142 | 1986 passed | 129 failed | 27 failed as expected
+assertions: 2147 | 1991 passed | 129 failed | 27 failed as expected
 

tests/SelfTest/Baselines/console.sw.approved.txt

@@ -5440,6 +5440,7 @@ with expansion:
 -------------------------------------------------------------------------------
 Generators internals
   Filter generator
+  Simple filtering
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
@@ -5464,8 +5465,47 @@ GeneratorsImpl.tests.cpp:<line number>: PASSED:
 with expansion:
   !false
 
+-------------------------------------------------------------------------------
+Generators internals
+  Filter generator
+  Filter out multiple elements at the start and end
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
+
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  REQUIRE_THROWS_AS( filter([] (int) { return false; }, value(1)), Catch::GeneratorException )
+  REQUIRE( gen.get() == 1 )
+with expansion:
+  1 == 1
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Generators internals
+  Filter generator
+  Throws on construction if it can't get initial element
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS_AS( filter([](int) { return false; }, value(1)), Catch::GeneratorException )
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS_AS( filter([](int) { return false; }, values({ 1, 2, 3 })), Catch::GeneratorException )
 
 -------------------------------------------------------------------------------
 Generators internals
@@ -17228,5 +17268,5 @@ Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
 test cases:  376 |  283 passed |  86 failed |  7 failed as expected
-assertions: 2159 | 1986 passed | 146 failed | 27 failed as expected
+assertions: 2164 | 1991 passed | 146 failed | 27 failed as expected
 

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="129" tests="2159" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="129" tests="2164" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="~[!nonportable]~[!benchmark]~[approvals] *"/>
@@ -698,7 +698,9 @@ Message.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Generators internals/Preset values" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Generator combinator" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Explicitly typed generator sequence" time="{duration}" status="run"/>
-    <testcase classname="<exe-name>.global" name="Generators internals/Filter generator" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Filter generator/Simple filtering" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Filter generator/Filter out multiple elements at the start and end" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Filter generator/Throws on construction if it can't get initial element" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Take generator/Take less" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Take generator/Take more" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Map with explicit return type" time="{duration}" status="run"/>

tests/SelfTest/Baselines/sonarqube.sw.approved.txt

@@ -94,7 +94,9 @@
     <testCase name="Generators internals/Preset values" duration="{duration}"/>
     <testCase name="Generators internals/Generator combinator" duration="{duration}"/>
     <testCase name="Generators internals/Explicitly typed generator sequence" duration="{duration}"/>
-    <testCase name="Generators internals/Filter generator" duration="{duration}"/>
+    <testCase name="Generators internals/Filter generator/Simple filtering" duration="{duration}"/>
+    <testCase name="Generators internals/Filter generator/Filter out multiple elements at the start and end" duration="{duration}"/>
+    <testCase name="Generators internals/Filter generator/Throws on construction if it can't get initial element" duration="{duration}"/>
     <testCase name="Generators internals/Take generator/Take less" duration="{duration}"/>
     <testCase name="Generators internals/Take generator/Take more" duration="{duration}"/>
     <testCase name="Generators internals/Map with explicit return type" duration="{duration}"/>

tests/SelfTest/Baselines/tap.sw.approved.txt

@@ -1373,7 +1373,17 @@ ok {test-number} - gen.get() == 3 for: 3 == 3
 # Generators internals
 ok {test-number} - !(gen.next()) for: !false
 # Generators internals
-ok {test-number} - filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+ok {test-number} - gen.get() == 1 for: 1 == 1
+# Generators internals
+ok {test-number} - gen.next() for: true
+# Generators internals
+ok {test-number} - gen.get() == 3 for: 3 == 3
+# Generators internals
+ok {test-number} - !(gen.next()) for: !false
+# Generators internals
+ok {test-number} - filter([](int) { return false; }, value(1)), Catch::GeneratorException
+# Generators internals
+ok {test-number} - filter([](int) { return false; }, values({ 1, 2, 3 })), Catch::GeneratorException
 # Generators internals
 ok {test-number} - gen.get() == 1 for: 1 == 1
 # Generators internals
@@ -4320,5 +4330,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2159
+1..2164
 

tests/SelfTest/Baselines/xml.sw.approved.txt

@@ -6183,6 +6183,7 @@ Nor would this
       <OverallResults successes="7" failures="0" expectedFailures="0"/>
     </Section>
     <Section name="Filter generator" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Section name="Simple filtering" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
         <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
             gen.get() == 1
@@ -6215,15 +6216,69 @@ Nor would this
             !false
           </Expanded>
         </Expression>
-      <Expression success="true" type="REQUIRE_THROWS_AS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <OverallResults successes="4" failures="0" expectedFailures="0"/>
+      </Section>
+      <OverallResults successes="4" failures="0" expectedFailures="0"/>
+    </Section>
+    <Section name="Filter generator" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Section name="Filter out multiple elements at the start and end" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-          filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+            gen.get() == 1
           </Original>
           <Expanded>
-          filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+            1 == 1
           </Expanded>
         </Expression>
-      <OverallResults successes="5" failures="0" expectedFailures="0"/>
+        <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.next()
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.get() == 3
+          </Original>
+          <Expanded>
+            3 == 3
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            !(gen.next())
+          </Original>
+          <Expanded>
+            !false
+          </Expanded>
+        </Expression>
+        <OverallResults successes="4" failures="0" expectedFailures="0"/>
+      </Section>
+      <OverallResults successes="4" failures="0" expectedFailures="0"/>
+    </Section>
+    <Section name="Filter generator" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Section name="Throws on construction if it can't get initial element" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE_THROWS_AS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            filter([](int) { return false; }, value(1)), Catch::GeneratorException
+          </Original>
+          <Expanded>
+            filter([](int) { return false; }, value(1)), Catch::GeneratorException
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE_THROWS_AS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            filter([](int) { return false; }, values({ 1, 2, 3 })), Catch::GeneratorException
+          </Original>
+          <Expanded>
+            filter([](int) { return false; }, values({ 1, 2, 3 })), Catch::GeneratorException
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <OverallResults successes="2" failures="0" expectedFailures="0"/>
     </Section>
     <Section name="Take generator" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
       <Section name="Take less" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
@@ -20183,6 +20238,6 @@ loose text artifact
     </Section>
     <OverallResult success="true"/>
   </TestCase>
-  <OverallResults successes="1986" failures="146" expectedFailures="27"/>
+  <OverallResults successes="1991" failures="146" expectedFailures="27"/>
   <OverallResultsCases successes="283" failures="86" expectedFailures="7"/>
 </Catch2TestRun>

tests/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp

@@ -50,14 +50,27 @@ TEST_CASE("Generators internals", "[generators][internals]") {
     }
     SECTION("Filter generator") {
         // Normal usage
-        auto gen = filter([] (int i) { return i != 2; }, values({ 2, 1, 2, 3, 2, 2 }));
+        SECTION("Simple filtering") {
+            auto gen = filter([](int i) { return i != 2; }, values({ 2, 1, 2, 3, 2, 2 }));
             REQUIRE(gen.get() == 1);
             REQUIRE(gen.next());
             REQUIRE(gen.get() == 3);
             REQUIRE_FALSE(gen.next());
+        }
+        SECTION("Filter out multiple elements at the start and end") {
+            auto gen = filter([](int i) { return i != 2; }, values({ 2, 2, 1, 3, 2, 2 }));
+            REQUIRE(gen.get() == 1);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 3);
+            REQUIRE_FALSE(gen.next());
+        }
 
-        // Completely filtered-out generator should throw on construction
+        SECTION("Throws on construction if it can't get initial element") {
-        REQUIRE_THROWS_AS(filter([] (int) { return false; }, value(1)), Catch::GeneratorException);
+            REQUIRE_THROWS_AS(filter([](int) { return false; }, value(1)), Catch::GeneratorException);
+            REQUIRE_THROWS_AS(
+                filter([](int) { return false; }, values({ 1, 2, 3 })),
+                Catch::GeneratorException);
+        }
     }
     SECTION("Take generator") {
         SECTION("Take less") {