added test cases for count function

Author: aman-godara

src/stdlib_strings.f90

@@ -95,7 +95,7 @@ module stdlib_strings
 
     !> Returns the number of times substring 'pattern' has appeared in the
     !> input string 'string'
-    !> [Specifications](link to the specs - to be completed)
+    !> [Specifications](../page/specs/stdlib_strings.html#count)
     !> Version: experimental
     interface count
         module procedure :: count_string_string

src/tests/string/test_string_functions.f90

@@ -4,7 +4,7 @@ module test_string_functions
     use stdlib_error, only : check
     use stdlib_string_type, only : string_type, assignment(=), operator(==), &
                                     to_lower, to_upper, to_title, to_sentence, reverse
-    use stdlib_strings, only: slice, find, replace_all                                   
+    use stdlib_strings, only: slice, find, replace_all, count
     use stdlib_optval, only: optval
     use stdlib_ascii, only : to_string
     implicit none
@@ -378,6 +378,49 @@ subroutine test_replace_all
 
     end subroutine test_replace_all
 
+    subroutine test_count
+        type(string_type) :: test_string_1, test_string_2, test_pattern_1, test_pattern_2
+        test_string_1 = "DNA sequence: AGAGAGAGTCCTGTCGAGA"
+        test_string_2 = "DNA sequence: GTCCTGTCCTGTCAGA"
+        test_pattern_1 = "AGA"
+        test_pattern_2 = "GTCCTGTC"
+
+        ! all 2 as string_type
+          call check(all(count([test_string_1, test_string_2], test_pattern_1) == [4, 1]), &
+                & 'count: all 2 as string_type, test case 1')
+          call check(all(count(test_string_1, [test_pattern_1, test_pattern_2], .false.) == [3, 1]), &
+                & 'count: all 2 as string_type, test case 2')
+          call check(count(test_string_2, test_pattern_1, .false.) == 1, &
+                & 'count: all 2 as string_type, test case 3')
+          call check(all(count([test_string_2, test_string_2, test_string_1], [test_pattern_2, &
+                & test_pattern_2, test_pattern_1], [.true., .false., .false.]) == [2, 1, 3]), &
+                & 'count: all 2 as string_type, test case 4')
+          call check(all(count([[test_string_1, test_string_2], [test_string_1, test_string_2]], [[test_pattern_1, &
+                & test_pattern_2], [test_pattern_2, test_pattern_1]], .true.) == [[4, 2], [1, 1]]), &
+                & 'count: all 2 as string_type, test case 5')
+        
+        ! 1 string_type and 1 character scalar
+          call check(all(count(test_string_1, ["AGA", "GTC"], [.true., .false.]) == [4, 2]), &
+                & 'count: 1 string_type and 1 character scalar, test case 1')
+          call check(all(count([test_string_1, test_string_2], ["CTC", "GTC"], [.true., .false.]) &
+                & == [0, 3]), 'count: 1 string_type and 1 character scalar, test case 2')
+          call check(all(count(["AGAGAGAGTCCTGTCGAGA", "AGAGAGAGTCCTGTCGAGA"], test_pattern_1, &
+                & [.false., .true.]) == [3, 4]), &
+                & 'count: 1 string_type and 1 character scalar, test case 3')
+          call check(count(test_string_1, "GAG") == 4, &
+                & 'count: 1 string_type and 1 character scalar, test case 4')
+          call check(count("DNA sequence: GTCCTGTCCTGTCAGA", test_pattern_2, .false.) == 1, &
+                & 'count: 1 string_type and 1 character scalar, test case 5')
+        
+        ! all 2 character scalar
+          call check(all(count("", ["mango", "trees"], .true.) == [0, 0]), &
+                & 'count: all 2 character scalar, test case 1')
+          call check(count("", "", .true.) == 0, 'count: all 2 character scalar, test case 2')
+          call check(all(count(["mango", "trees"], "", .true.) == [0, 0]), &
+                & 'count: all 2 character scalar, test case 3')
+
+    end subroutine test_count
+
 end module test_string_functions
 
 
@@ -394,5 +437,6 @@ program tester
     call test_slice_gen
     call test_find
     call test_replace_all
+    call test_count
 
 end program tester