Feature/operator overloading (#18)

* overload len magic function

* operator (+,*) overloading

* add operator overloading errors

* add tests for len, addition and multipication

* `CHANGELOG.md` updated

* `auto.pep8.sh` applied

* feedback applied

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Changed
 ## [0.1] - 2024-06-05
 ### Added
+- `addition` and `multipication` operators overload
+- `len` magic overload
 - `Primer` class
 - Molecular weight calculation
 - GC content calculation

opr/params.py

@@ -21,3 +21,6 @@
 PRIMER_SEQUENCE_VALID_GC_CONTENT_RANGE_WARNING = "The recommended range for GC content is between 30% and 80%."
 PRIMER_READ_ONLY_ATTRIBUTE_ERROR = "This attribute is read-only."
 PRIMER_NOT_REMOVABLE_ATTRIBUTE_ERROR = "This attribute is not removable."
+
+PRIMER_ADDITION_ERROR = "You can only add two Primer objects."
+PRIMER_MULTIPICATION_ERROR = "The primer sequence can only be multiplied by an integer."

opr/primer.py

@@ -8,6 +8,7 @@
 from .params import PRIMER_READ_ONLY_ATTRIBUTE_ERROR, PRIMER_NOT_REMOVABLE_ATTRIBUTE_ERROR
 from .params import A_WEIGHT, T_WEIGHT, C_WEIGHT, G_WEIGHT, ANHYDROUS_MOLECULAR_WEIGHT_CONSTANT
 from .params import DNA_COMPLEMENT_MAP
+from .params import PRIMER_ADDITION_ERROR, PRIMER_MULTIPICATION_ERROR
 
 
 class Primer:
@@ -30,6 +31,38 @@ def __init__(self, primer_sequence):
         self._molecular_weight = None
         self._gc_content = None
 
+    def __len__(self):
+        """
+        Return the length of the Primer sequence.
+
+        :return: length of the Primer sequence
+        """
+        return len(self._sequence)
+
+    def __add__(self, other_primer):
+        """
+        Concatenate the sequences of the current Primer with another one.
+
+        :param other_primer: another Primer to concat its sequence to the current Primer
+        :type other_primer: Primer
+        :return: new Primer with concatenated sequence
+        """
+        if isinstance(other_primer, Primer):
+            return Primer(self._sequence + other_primer._sequence)
+        raise OPRBaseError(PRIMER_ADDITION_ERROR)
+
+    def __mul__(self, number):
+        """
+        Multiply the Primer sequence `number` times.
+
+        :param number: times to concat the Primer sequence to itself
+        :type number: int
+        :return: new Primer with multiplied sequence
+        """
+        if isinstance(number, int):
+            return Primer(self._sequence * number)
+        raise OPRBaseError(PRIMER_MULTIPICATION_ERROR)
+
     def reverse(self, inplace=False):
         """
         Reverse sequence.

tests/test_operations.py

@@ -33,4 +33,17 @@ def test_complement_3(): #Reference: https://www.qiagen.com/us/applications/enzy
     oprimer.complement(inplace=True)
     assert oprimer.sequence == "TAGCCGATTTAGCCGATT"
 
-
+def test_length():
+    oprimer = Primer("ATCGGCTAAATCGGCTAA")
+    assert len(oprimer) == 18
+
+def test_addition():
+    oprimer_1 = Primer("ATCG")
+    oprimer_2 = Primer("GATC")
+    oprimer_concat = oprimer_1 + oprimer_2
+    assert oprimer_concat.sequence == "ATCGGATC"
+
+def test_multiply():
+    oprimer_1 = Primer("ATCG")
+    oprimer_concat = oprimer_1 * 4
+    assert oprimer_concat.sequence == "ATCGATCGATCGATCG"