[array] add Remove() and RemoveMatching() (#7817)

This commit adds `Remove/RemoveMatching()` in `Array` class which
remove a given or a matched element from the array. To remove the
element, it is replaced by the last element from array, so the order
of items in the array can change after call to these method.

This commit also updated unit test `test_array` to verify the behavior
of newly added methods.

tests/unit/test_array.cpp

@@ -35,6 +35,7 @@
 
 #include "common/array.hpp"
 #include "common/debug.hpp"
+#include "common/equatable.hpp"
 #include "common/instance.hpp"
 #include "common/type_traits.hpp"
 
@@ -175,7 +176,7 @@ void TestArrayCopyAndFindMatching(void)
 {
     constexpr uint16_t kMaxSize = 10;
 
-    struct Entry
+    struct Entry : public Unequatable<Entry>
     {
         Entry(void) = default;
 
@@ -185,7 +186,7 @@ void TestArrayCopyAndFindMatching(void)
         {
         }
 
-        bool operator==(const Entry &aOther) { return (mName == aOther.mName) && (mYear == aOther.mYear); }
+        bool operator==(const Entry &aOther) const { return (mName == aOther.mName) && (mYear == aOther.mYear); }
         bool Matches(const char *aName) const { return strcmp(aName, mName) == 0; }
         bool Matches(uint16_t aYear) const { return aYear == mYear; }
 
@@ -271,6 +272,51 @@ void TestArrayCopyAndFindMatching(void)
     VerifyOrQuit(array2.FindMatching(static_cast<uint16_t>(2001)) == nullptr);
     VerifyOrQuit(!array2.ContainsMatching(static_cast<uint16_t>(2001)));
 
+    // Test removing of entries at every index.
+
+    array1 = array2;
+
+    for (const Entry &entryToRemove : array1)
+    {
+        Entry *match;
+
+        // Test `Remove()`
+
+        array2 = array1;
+        match  = array2.Find(entryToRemove);
+        VerifyOrQuit(match != nullptr);
+        array2.Remove(*match);
+
+        VerifyOrQuit(array2.GetLength() == array1.GetLength() - 1);
+
+        for (const Entry &entry : array2)
+        {
+            VerifyOrQuit(entry != entryToRemove);
+            VerifyOrQuit(array1.Contains(entry));
+        }
+
+        // Test `RemoveMatching()`
+
+        array2 = array1;
+        array2.RemoveMatching(entryToRemove.mName);
+
+        printf("\nArray after `RemoveMatching()` on entry %s\n", entryToRemove.mName);
+
+        VerifyOrQuit(array2.GetLength() == array1.GetLength() - 1);
+
+        for (const Entry &entry : array2)
+        {
+            printf("- Name:%-3s Year:%d\n", entry.mName, entry.mYear);
+            VerifyOrQuit(entry != entryToRemove);
+            VerifyOrQuit(array1.Contains(entry));
+        }
+
+        // Test `RemoveMatchin()` with a non-existing match
+
+        array2.RemoveMatching(entryToRemove.mName);
+        VerifyOrQuit(array2.GetLength() == array1.GetLength() - 1);
+    }
+
     printf("\n");
 }