Add SUCCEED and FAIL docs next to SKIP docs

docs/skipping-passing-failing.md

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+<a id="top"></a>
+# Explicitly skipping, passing, and failing tests at runtime
+
+## Skipping Test Cases at Runtime
+
+> [Introduced](https://github.com/catchorg/Catch2/pull/2360) in Catch2 X.Y.Z.
+
+In some situations it may not be possible to meaningfully execute a test case, for example when the system under test is missing certain hardware capabilities.
+If the required conditions can only be determined at runtime, it often doesn't make sense to consider such a test case as either passed or failed, because it simply can not run at all.
+To properly express such scenarios, Catch2 allows to explicitly _skip_ test cases, using the `SKIP` macro:
+
+**SKIP(** [streamable expression] **)**
+
+Example usage:
+
+```c++
+TEST_CASE("copy files between drives") {
+    if(getNumberOfHardDrives() < 2) {
+        SKIP("at least two hard drives required");
+    }
+    // ...
+}
+```
+
+This test case is then reported as _skipped_ instead of _passed_ or _failed_.
+
+The `SKIP` macro behaves similarly to an explicit [`FAIL`](logging.md#top), in that it is the last expression that will be executed:
+
+```c++
+TEST_CASE("my test") {
+    printf("foo");
+    SKIP();
+    printf("bar"); // not printed
+}
+```
+
+However a failed assertion _before_ a `SKIP` still causes the entire test case to fail:
+
+```c++
+TEST_CASE("failing test") {
+    CHECK(1 == 2);
+    SKIP();
+}
+```
+
+### Interaction with Sections and Generators
+
+Sections, nested sections as well as test cases with [generators](generators.md#top) can all be individually skipped, with the rest executing as usual:
+
+```c++
+TEST_CASE("complex test case") {
+  int value = GENERATE(2, 4, 6);
+  SECTION("a") {
+    SECTION("a1") { CHECK(value < 8); }
+    SECTION("a2") {
+      if (value == 4) {
+        SKIP();
+      }
+      CHECK(value % 2 == 0);
+    }
+  }
+}
+```
+
+This test case will report 5 passing assertions; one for each of the three values in section `a1`, as well as one for each in `a2`, except for when `value == 4`.
+
+Note that as soon as one section is skipped, the entire test case will be reported as _skipped_ (unless there is a failing assertion, in which case it will be reported as _failed_ instead).
+
+If all test cases in a run are skipped, Catch2 returns a non-zero exit code by default.
+This can be overridden using the [--allow-running-no-tests](command-line.md#no-tests-override) flag.
+
+
+## Passing and failing test cases
+
+Test cases can also be explicitly passed or failed, without the use of
+assertions, and with a specific message. This can be useful to handle
+complex preconditions/postconditions and give useful error messages
+when they fail.
+
+* `SUCCEED( [streamable expression] )`
+
+`SUCCEED` is morally equivalent with `INFO( [streamable expression] ); REQUIRE( true );`.
+Note that it does not stop further test execution, so it cannot be used
+to guard failing assertions from being executed.
+
+_In practice, `SUCCEED` is usually used as a test placeholder, to avoid
+[failing a test case due to missing assertions](command-line.md#warnings)._
+
+```cpp
+TEST_CASE( "SUCCEED showcase" ) {
+    int I = 1;
+    SUCCEED( "I is " << I );
+    // ... execution continues here ...
+}
+```
+
+* `FAIL( [streamable expression] )`
+
+`FAIL` is morally equivalent with `INFO( [streamable expression] ); REQUIRE( false );`.
+
+_In practice, `FAIL` is usually used to stop executing test that is currently
+known to be broken, but has to be fixed later._
+
+```cpp
+TEST_CASE( "FAIL showcase" ) {
+    FAIL( "This test case causes segfault, which breaks CI." );
+    // ... this will not be executed ...
+}
+```
+
+
+---
+
+[Home](Readme.md#top)